diff --git a/server/gameserver/bullet.cc b/server/gameserver/bullet.cc
index e9ffb0d..097431d 100644
--- a/server/gameserver/bullet.cc
+++ b/server/gameserver/bullet.cc
@@ -26,32 +26,44 @@ void Bullet::Update(int delta_time)
 {
     pos = pos + dir * gun_meta->i->bullet_speed() / 20.0f;
     float distance = (pos - born_pos).Norm();
-    if (meta->i->_inventory_slot() == 5 ||
-        meta->i->_inventory_slot() == 6) {
-        std::vector<Entity*> objects;
-        int detection_flags = 0;
-        {
-            a8::SetBitFlag(detection_flags, ET_Obstacle);
-            a8::SetBitFlag(detection_flags, ET_Building);
-        }
-        room->CollisionDetection(this, detection_flags, objects);
-        if (!objects.empty() || distance >= fly_distance) {
+    room->grid_service.MoveBullet(this);
+    if (room->OverBorder(pos, gun_meta->i->bullet_rad())) {
+        if (IsBomb()){
             ProcBomb();
+        } else {
+           room->RemoveObjectLater(this);
         }
     } else {
-        std::vector<Entity*> objects;
-        int detection_flags = 0;
-        {
-            a8::SetBitFlag(detection_flags, ET_Obstacle);
-            a8::SetBitFlag(detection_flags, ET_Player);
-        }
-        room->CollisionDetection(this, detection_flags, objects);
-        if (!objects.empty() || distance > gun_meta->i->range()) {
-            deleted = true;
-            if (!objects.empty()) {
-                OnHit(objects);
+        std::set<Entity*> objects;
+        for (auto& grid : grid_list) {
+            for (Entity* entity : grid->entity_list) {
+                switch (entity->entity_type) {
+                case ET_Obstacle:
+                case ET_Building:
+                case ET_Player:
+                    {
+                        if (TestCollision(entity)) {
+                            objects.insert(entity);
+                        }
+                    }
+                    break;
+                default:
+                    {
+                    }
+                    break;
+                }
+            }
+        }//end for
+        if (!objects.empty() || distance > gun_meta->i->range()) {
+            if (IsBomb()) {
+                ProcBomb();
+            } else {
+                deleted = true;
+                if (!objects.empty()) {
+                    OnHit(objects);
+                }
+                room->RemoveObjectLater(this);
             }
-            room->RemoveObjectLater(this);
         }
     }
 }
@@ -67,7 +79,7 @@ void Bullet::RecalcSelfCollider()
     self_collider_->rad = gun_meta->i->bullet_rad();
 }
 
-void Bullet::OnHit(std::vector<Entity*>& objects)
+void Bullet::OnHit(std::set<Entity*>& objects)
 {
     for (auto& target : objects) {
         switch (target->entity_type) {
@@ -125,3 +137,9 @@ void Bullet::ProcBomb()
     }
     room->RemoveObjectLater(this);
 }
+
+bool Bullet::IsBomb()
+{
+    return meta->i->_inventory_slot() == 5 ||
+        meta->i->_inventory_slot() == 6;
+}
diff --git a/server/gameserver/bullet.h b/server/gameserver/bullet.h
index 850e5d9..7718002 100644
--- a/server/gameserver/bullet.h
+++ b/server/gameserver/bullet.h
@@ -29,8 +29,9 @@ class Bullet : public Entity
 
  private:
 
-    void OnHit(std::vector<Entity*>& objects);
+    void OnHit(std::set<Entity*>& objects);
     void ProcBomb();
+    bool IsBomb();
 
 private:
     CircleCollider* self_collider_ = nullptr;
diff --git a/server/gameserver/entity.cc b/server/gameserver/entity.cc
index c2cebdb..32ac995 100644
--- a/server/gameserver/entity.cc
+++ b/server/gameserver/entity.cc
@@ -4,6 +4,7 @@
 #include "collider.h"
 #include "room.h"
 #include "building.h"
+#include "human.h"
 
 Entity::Entity()
 {
@@ -71,7 +72,9 @@ void Entity::FindLocationWithTarget(Entity* target)
         {
             a8::SetBitFlag(detection_flags, ET_Obstacle);
         }
+        #if 0
         room->CollisionDetection(this, detection_flags, objects);
+        #endif
         if (objects.empty()) {
             break;
         }
@@ -83,18 +86,15 @@ void Entity::FindLocationWithTarget(Entity* target)
 
 void Entity::BroadcastFullState()
 {
-#if 0
-    room->TouchPlayerList(a8::XParams()
-                          .SetSender(obstacle),
-                          [] (Player* hum, a8::XParams& param)
-                          {
-                              Obstacle* obstacle = (Obstacle*)param.sender.GetUserData();
-                              hum->AddToNewObjects(obstacle);
-                          });
-#endif
+    std::set<GridCell*> grid_list;
+    room->grid_service.Get123456789(grid_id, grid_list);
+    for (auto& grid : grid_list) {
+        for (Human* hum : grid->human_list) {
+            hum->AddToNewObjects(this);
+        }
+    }
 }
 
 void Entity::BroadcastDeleteState()
 {
-
 }
diff --git a/server/gameserver/gridservice.cc b/server/gameserver/gridservice.cc
index 7674a5a..fc9b192 100644
--- a/server/gameserver/gridservice.cc
+++ b/server/gameserver/gridservice.cc
@@ -2,6 +2,7 @@
 
 #include "gridservice.h"
 #include "human.h"
+#include "bullet.h"
 
 GridService::GridService()
 {
@@ -139,6 +140,40 @@ void GridService::MoveHuman(Human* hum)
     }
 }
 
+void GridService::AddBullet(Bullet* bullet)
+{
+    int x = (int)bullet->pos.x + cell_width_;
+    int y = (int)bullet->pos.y + cell_width_;
+    if (BroderOverFlow(x, y)) {
+        abort();
+    }
+    bullet->grid_id = x/cell_width_ + (y/cell_width_) * cell_count_per_row_;
+    if (bullet->grid_id == 0 || bullet->grid_id > max_grid_id_) {
+        abort();
+    }
+    cells_[bullet->grid_id].bullet_list.insert(bullet);
+    Get123456789(bullet->grid_id, bullet->grid_list);
+}
+
+void GridService::MoveBullet(Bullet* bullet)
+{
+    int new_x = (int)bullet->pos.x + cell_width_;
+    int new_y = (int)bullet->pos.y + cell_width_;
+    int new_grid_id = new_x/cell_width_ + (new_y/cell_width_) * cell_count_per_row_;
+    if (new_grid_id != bullet->grid_id) {
+        std::set<GridCell*> inc_grid_list;
+        std::set<GridCell*> dec_grid_list;
+        std::set<GridCell*> old_grid_list = bullet->grid_list;
+        ComputeDiff(bullet->grid_id, new_grid_id,
+                    bullet->grid_list,
+                    inc_grid_list,
+                    dec_grid_list);
+        cells_[bullet->grid_id].bullet_list.erase(bullet);
+        cells_[new_grid_id].bullet_list.insert(bullet);
+        bullet->grid_id = new_grid_id;
+    }
+}
+
 void GridService::AddEntity(Entity* entity)
 {
     int x = (int)entity->pos.x + cell_width_;
diff --git a/server/gameserver/gridservice.h b/server/gameserver/gridservice.h
index 5d892b6..14fd45c 100644
--- a/server/gameserver/gridservice.h
+++ b/server/gameserver/gridservice.h
@@ -2,11 +2,13 @@
 
 class Entity;
 class Human;
+class Bullet;
 
 struct GridCell
 {
     std::set<Human*> human_list;
     std::set<Entity*> entity_list;
+    std::set<Bullet*> bullet_list;
 };
 
 /*
@@ -37,6 +39,9 @@ class GridService
     void AddHuman(Human* hum);
     void MoveHuman(Human* hum);
 
+    void AddBullet(Bullet* bullet);
+    void MoveBullet(Bullet* bullet);
+
     void AddEntity(Entity* entity);
 
     bool HumanInGridList(Human* hum, std::set<GridCell*>& grid_list);
diff --git a/server/gameserver/human.cc b/server/gameserver/human.cc
index 23620af..e293438 100644
--- a/server/gameserver/human.cc
+++ b/server/gameserver/human.cc
@@ -246,27 +246,8 @@ void Human::RecalcSelfCollider()
 
 bool Human::IsCollision()
 {
-    //检查x轴
-    {
-        int left_x = pos.x - meta->i->radius();
-        if (left_x < 0.001f) {
-            return true;
-        }
-        int right_x = pos.x + meta->i->radius();
-        if (right_x > MAP_WIDTH) {
-            return true;
-        }
-    }
-    //检查y轴
-    {
-        int up_y = pos.y + meta->i->radius();
-        if (up_y > MAP_HEIGHT) {
-            return true;
-        }
-        int down_y = pos.y - meta->i->radius();
-        if (down_y < 0.001f) {
-            return true;
-        }
+    if (room->OverBorder(pos, meta->i->radius())){
+        return true;
     }
 
     if (a8::HasBitFlag(status, HS_Jump)) {
@@ -305,16 +286,6 @@ bool Human::IsCollision()
     return !objects.empty();
 }
 
-ColliderComponent* Human::GetFirstCollision()
-{
-    int detection_flags = 0;
-    a8::SetBitFlag(detection_flags, ET_Obstacle);
-    a8::SetBitFlag(detection_flags, ET_Building);
-    std::vector<Entity*> objects;
-    room->CollisionDetection(this, detection_flags, objects);
-    return objects.empty() ? *objects[0]->colliders.begin() : nullptr;
-}
-
 void Human::FindPath()
 {
     Vector2D old_pos = pos;
@@ -669,7 +640,9 @@ void Human::FindLocation()
             a8::SetBitFlag(detection_flags, ET_Obstacle);
             a8::SetBitFlag(detection_flags, ET_Player);
         }
+        #if 0
         room->CollisionDetection(this, detection_flags, objects);
+        #endif
         if (objects.empty()) {
             return;
         }
diff --git a/server/gameserver/human.h b/server/gameserver/human.h
index b51a903..242c04b 100644
--- a/server/gameserver/human.h
+++ b/server/gameserver/human.h
@@ -98,7 +98,6 @@ class Human : public Entity
     void Shot(Vector2D& target_dir);
     void RecalcSelfCollider();
     bool IsCollision();
-    ColliderComponent* GetFirstCollision();
     void FindPath();
     float GetRadius();
     float GetMaxHP();
diff --git a/server/gameserver/room.cc b/server/gameserver/room.cc
index c37c556..2a02d20 100644
--- a/server/gameserver/room.cc
+++ b/server/gameserver/room.cc
@@ -233,54 +233,6 @@ Human* Room::FindEnemy(Human* hum)
     return !enemys.empty() ? enemys[0] : nullptr;
 }
 
-void Room::CollisionDetection(Entity* sender, int detection_flags, std::vector<Entity*>& objects)
-{
-    assert(uniid_hash_.size() < 2000);
-    for (auto& pair : uniid_hash_) {
-        if (sender == pair.second) {
-            continue;
-        }
-        #if 1
-        if (std::abs(sender->pos.x - pair.second->pos.x) > 1000 ||
-            std::abs(sender->pos.y - pair.second->pos.y) > 1000){
-            continue;
-        }
-        #endif
-        if (a8::HasBitFlag(detection_flags, ET_Player) && pair.second->entity_type == ET_Player) {
-            if (sender->entity_type == ET_Bullet) {
-                Bullet* bullet = (Bullet*)sender;
-                Human* hum = (Human*)pair.second;
-#if 1
-                if (hum != bullet->player) {
-#else
-                if (hum != bullet->player &&
-                    (hum->team_id == 0 || bullet->player->team_id != hum->team_id)) {
-#endif
-                    if (bullet->TestCollision(hum)) {
-                        objects.push_back(hum);
-                    }
-                }
-            }
-        }
-        if (a8::HasBitFlag(detection_flags, ET_Obstacle) && pair.second->entity_type == ET_Obstacle) {
-            if (sender->entity_type == ET_Bullet || sender->entity_type == ET_Player) {
-                if (pair.second != sender &&
-                    (sender->last_collision_door == nullptr || sender->last_collision_door != pair.second) &&
-                    sender->TestCollision(pair.second)) {
-                    objects.push_back(pair.second);
-                }
-            }
-        }
-        if (a8::HasBitFlag(detection_flags, ET_Building) && pair.second->entity_type == ET_Building) {
-            if (sender->entity_type == ET_Bullet || sender->entity_type == ET_Player) {
-                if (pair.second != sender && sender->TestCollision(pair.second)) {
-                    objects.push_back(pair.second);
-                }
-            }
-        }
-    }
-}
-
 void Room::BuildingBoxBoundCollisionDetection(Entity* sender, std::vector<Entity*>& objects)
 {
     ColliderComponent* a_collider = sender->GetBoxBound();
@@ -486,6 +438,7 @@ void Room::CreateBullet(Human* hum, MetaData::Equip* gun_meta,
     bullet->entity_uniid = AllocUniid();
     bullet->Initialize();
     AddObjectLater(bullet);
+    grid_service.AddBullet(bullet);
 }
 
 void Room::RemoveObjectLater(Entity* entity)
@@ -534,6 +487,33 @@ void Room::OnHumanDie(Human* hum)
     --alive_count_;
 }
 
+bool Room::OverBorder(const Vector2D pos, float radius)
+{
+    //检查x轴
+    {
+        int left_x = pos.x - radius;
+        if (left_x < 0.001f) {
+            return true;
+        }
+        int right_x = pos.x + radius;
+        if (right_x > MAP_WIDTH) {
+            return true;
+        }
+    }
+    //检查y轴
+    {
+        int up_y = pos.y + radius;
+        if (up_y > MAP_HEIGHT) {
+            return true;
+        }
+        int down_y = pos.y - radius;
+        if (down_y < 0.001f) {
+            return true;
+        }
+    }
+    return false;
+}
+
 int Room::NewTeam()
 {
     ++current_teamid;
diff --git a/server/gameserver/room.h b/server/gameserver/room.h
index fc53683..449c67f 100644
--- a/server/gameserver/room.h
+++ b/server/gameserver/room.h
@@ -57,7 +57,6 @@ public:
     void AddPlayer(Player* hum);
     Human* FindEnemy(Human* hum);
 
-    void CollisionDetection(Entity* sender, int detection_flags, std::vector<Entity*>& objects);
     void BuildingBoxBoundCollisionDetection(Entity* sender, std::vector<Entity*>& objects);
     void RemoveObjectLater(Entity* entity);
 
@@ -80,6 +79,7 @@ public:
                       Vector2D pos, Vector2D dir, float fly_distance);
 
     void OnHumanDie(Human* hum);
+    bool OverBorder(const Vector2D pos, float radius);
 
 private:
     unsigned short AllocUniid();