diff --git a/server/gameserver/room.cc b/server/gameserver/room.cc
index 9cc0a84..8a3defa 100644
--- a/server/gameserver/room.cc
+++ b/server/gameserver/room.cc
@@ -180,6 +180,7 @@ void Room::AddPlayer(Player* hum)
 unsigned short Room::AllocUniid()
 {
     while (GetEntityByUniId(++current_uniid) ||
+           later_add_hash_.find(current_uniid) != later_add_hash_.end() ||
            current_uniid == 0) {}
     return current_uniid;
 }
@@ -503,7 +504,6 @@ void Room::RemoveObjectLater(Entity* entity)
     auto remove_func = [] (const a8::XParams& param)
                        {
                            Entity* entity = (Entity*)param.sender.GetUserData();
-                           entity->room->uniid_hash_.erase(entity->entity_uniid);
                            switch (entity->entity_type) {
                            case ET_Bullet:
                                {
@@ -521,6 +521,7 @@ void Room::RemoveObjectLater(Entity* entity)
                                }
                                break;
                            }
+                           entity->room->uniid_hash_.erase(entity->entity_uniid);
                            delete entity;
                        };
     xtimer.AddDeadLineTimerAndAttach(0,
@@ -969,5 +970,19 @@ Obstacle* Room::InternalCreateObstacle(int id, float x, float y,
 
 void Room::AddObjectLater(Entity* entity)
 {
-
+    auto add_func = [] (const a8::XParams& param)
+                       {
+                           Entity* entity = (Entity*)param.sender.GetUserData();
+                           if (entity->entity_type == ET_Bullet) {
+                               entity->room->moveable_hash_[entity->entity_uniid] = entity;
+                           }
+                           entity->room->uniid_hash_[entity->entity_uniid] = entity;
+                           entity->room->later_add_hash_.erase(entity->entity_uniid);
+                       };
+    later_add_hash_[entity->entity_uniid] = entity;
+    xtimer.AddDeadLineTimerAndAttach(0,
+                                     a8::XParams()
+                                     .SetSender(entity),
+                                     add_func,
+                                     &entity->xtimer_attacher.timer_list_);
 }
diff --git a/server/gameserver/room.h b/server/gameserver/room.h
index 12a393e..fc53683 100644
--- a/server/gameserver/room.h
+++ b/server/gameserver/room.h
@@ -75,7 +75,6 @@ public:
     void ScatterDrop(Vector2D center, int drop_id);
     void DropItem(Vector2D pos, int item_id, int item_count);
 
-    Obstacle* CreateObstacle(int id, float x, float y);
     void CreateLoot(int equip_id, Vector2D pos, int count);
     void CreateBullet(Human* hum, MetaData::Equip* gun_meta,
                       Vector2D pos, Vector2D dir, float fly_distance);
@@ -95,6 +94,7 @@ private:
     void AirDrop(int appear_time, int box_id);
     void ShuaPlane();
     int NewTeam();
+    Obstacle* CreateObstacle(int id, float x, float y);
     void CreateThings();
     void CreateBuilding(int thing_id, float building_x, float building_y);
     Obstacle* InternalCreateObstacle(int id, float x, float y,
@@ -115,5 +115,6 @@ private:
     std::map<std::string, Player*> accountid_hash_;
     std::map<unsigned short, Entity*> moveable_hash_;
     std::map<unsigned short, Entity*> uniid_hash_;
+    std::map<unsigned short, Entity*> later_add_hash_;
     std::map<unsigned short, Human*> human_hash_;
 };