diff --git a/server/gameserver/android.ai.cc b/server/gameserver/android.ai.cc
index 4ccba14..a4bac03 100644
--- a/server/gameserver/android.ai.cc
+++ b/server/gameserver/android.ai.cc
@@ -19,13 +19,12 @@ AndroidAI::~AndroidAI()
 
 void AndroidAI::Update(int delta_time)
 {
-    Human* hum = (Human*)owner;
     state_elapsed_time_ += delta_time;
-    if (hum->dead) {
+    if (HumMaster()->dead) {
         return;
     }
-    if (hum->playing_skill) {
-        hum->UpdateSkill();
+    if (HumMaster()->playing_skill) {
+        HumMaster()->UpdateSkill();
     }
     switch (state_) {
     case AS_thinking:
@@ -42,9 +41,22 @@ void AndroidAI::Update(int delta_time)
         break;
     case AS_moving:
         {
+            bool need_chg = true;
             if (state_elapsed_time_ < 1000 + rand() % 2000) {
                 DoMove();
-            } else {
+                need_chg = false;
+            } else if (locked_enemy_ && !locked_enemy_->dead &&
+                       HumMaster()->pos.Distance(locked_enemy_->pos) < MetaMgr::Instance()->robot_pursuit_range) {
+                if (HumMaster()->pos.Distance(locked_enemy_->pos) < MetaMgr::Instance()->robot_attack_range) {
+                    ChangeToState(AS_attack);
+                } else {
+                    HumMaster()->move_dir = locked_enemy_->pos - HumMaster()->pos;
+                    HumMaster()->move_dir.Normalize();
+                    DoMove();
+                }
+                need_chg = false;
+            }
+            if (need_chg) {
                 int rnd = rand();
                 if (rnd % 100 < 30) {
                     ChangeToState(AS_thinking);
@@ -56,9 +68,20 @@ void AndroidAI::Update(int delta_time)
         break;
     case AS_attack:
         {
+            bool need_chg = true;
             if (state_elapsed_time_ < 1000) {
                 DoAttack();
-            } else {
+                need_chg = false;
+            } else if (locked_enemy_ && locked_enemy_->dead &&
+                       HumMaster()->pos.Distance(locked_enemy_->pos) < MetaMgr::Instance()->robot_pursuit_range) {
+                if (HumMaster()->pos.Distance(locked_enemy_->pos) > MetaMgr::Instance()->robot_attack_range) {
+                    ChangeToState(AS_moving);
+                } else {
+                    DoAttack();
+                }
+                need_chg = false;
+            }
+            if (need_chg) {
                 int rnd = rand();
                 if (rnd % 100 < 30) {
                     ChangeToState(AS_moving);
@@ -68,6 +91,8 @@ void AndroidAI::Update(int delta_time)
             }
         }
         break;
+    default:
+        break;
     }
 }
 
@@ -105,11 +130,21 @@ void AndroidAI::ChangeToState(AndroidState_e to_state)
     switch (state_) {
     case AS_moving:
         {
-            Human* hum = (Human*)owner;
-            hum->move_dir = a8::Vec2(1.0f, 0);
-            hum->move_dir.Rotate(a8::RandAngle());
-            hum->move_dir.Normalize();
-            hum->attack_dir = hum->move_dir;
+            if (locked_enemy_) {
+                a8::Vec2 move_dir = locked_enemy_->pos - HumMaster()->pos;
+                if (std::abs(move_dir.x) > 0.00001f ||
+                    std::abs(move_dir.y) > 0.00001f) {
+                    HumMaster()->move_dir = move_dir;
+                    HumMaster()->move_dir.Normalize();
+                } else {
+                    return;
+                }
+            } else {
+                HumMaster()->move_dir = a8::Vec2(1.0f, 0);
+                HumMaster()->move_dir.Rotate(a8::RandAngle());
+                HumMaster()->move_dir.Normalize();
+            }
+            HumMaster()->attack_dir = HumMaster()->move_dir;
         }
         break;
     default:
@@ -119,47 +154,44 @@ void AndroidAI::ChangeToState(AndroidState_e to_state)
 
 void AndroidAI::DoMove()
 {
-    Human* hum = (Human*)owner;
-    if (hum->HasBuffEffect(kBET_Vertigo) || hum->HasBuffEffect(kBET_Dcgr)) {
+    if (HumMaster()->HasBuffEffect(kBET_Vertigo) || HumMaster()->HasBuffEffect(kBET_Dcgr)) {
         return;
     }
     if (owner->updated_times % 2 == 0) {
-        Human* hum = (Human*)owner;
-        int speed = std::max(1, (int)hum->GetSpeed());
+        int speed = std::max(1, (int)HumMaster()->GetSpeed());
         for (int i = 0; i < speed; ++i) {
-            a8::Vec2 old_pos = hum->pos;
-            hum->pos = hum->pos + hum->move_dir;
-            if (hum->IsCollisionInMapService()) {
-                hum->pos = old_pos;
+            a8::Vec2 old_pos = HumMaster()->pos;
+            HumMaster()->pos = HumMaster()->pos + HumMaster()->move_dir;
+            if (HumMaster()->IsCollisionInMapService()) {
+                HumMaster()->pos = old_pos;
                 if (i == 0) {
-                    hum->FindPath();
+                    HumMaster()->FindPath();
                 }
                 break;
             }
-            hum->room->grid_service.MoveHuman(hum);
+            HumMaster()->room->grid_service.MoveHuman(HumMaster());
         }
-        hum->CheckGrass();
+        HumMaster()->CheckGrass();
     }
 }
 
 void AndroidAI::DoAttack()
 {
-    Human* hum = (Human*)owner;
-    if (hum->room->gas_data.gas_mode == kGasInactive) {
+    if (HumMaster()->room->gas_data.gas_mode == kGasInactive) {
         return;
     }
-    if (hum->HasBuffEffect(kBET_Vertigo) || hum->HasBuffEffect(kBET_Dcgr)) {
+    if (HumMaster()->HasBuffEffect(kBET_Vertigo) || HumMaster()->HasBuffEffect(kBET_Dcgr)) {
         return;
     }
     if (owner->updated_times % 10 == 0) {
-        Human* enemy = owner->room->FindEnemy((Human*)owner);
+        Human* enemy = locked_enemy_ ? locked_enemy_ : owner->room->FindEnemy(HumMaster());
         if (enemy &&
             !enemy->HasBuffEffect(kBET_Invincible) &&
             !enemy->HasBuffEffect(kBET_Hide) &&
             !enemy->HasBuffEffect(kBET_InGrass)
             ) {
-            Human* sender = (Human*)owner;
-            if (sender->CanUseSkill()) {
+            if (HumMaster()->CanUseSkill() &&
+                HumMaster()->pos.Distance(enemy->pos) < HumMaster()->tank_meta_->i->atk_range()) {
                 UseSkill(enemy);
             } else {
                 Shot(enemy);
@@ -170,47 +202,61 @@ void AndroidAI::DoAttack()
 
 void AndroidAI::Shot(Human* enemy)
 {
-    Human* sender = (Human*)owner;
-    a8::Vec2 shot_dir = enemy->pos - sender->pos;
-    if (std::abs(shot_dir.x) > FLT_EPSILON ||
-        std::abs(shot_dir.y) > FLT_EPSILON) {
-        shot_dir.Normalize();
-        shot_dir.Rotate((rand() % 10) / 180.0f);
-        sender->attack_dir = shot_dir;
-        if (sender->curr_weapon->meta->NeedTrace()) {
-            sender->shot_target_id = enemy->entity_uniid;
-        } else {
-            sender->shot_target_id = 0;
+    if (enemy->HasBuffEffect(kBET_Hide) ||
+        enemy->HasBuffEffect(kBET_Invincible) ||
+        enemy->dead
+        ) {
+        return;
+    }
+    if (((HumMaster()->room->frameno - HumMaster()->last_shot_frameno_) * (1000 / kSERVER_FRAME_RATE)) >=
+        HumMaster()->curr_weapon->meta->i->fire_rate()
+        ) {
+        a8::Vec2 shot_dir = enemy->pos - HumMaster()->pos;
+        if (std::abs(shot_dir.x) > FLT_EPSILON ||
+            std::abs(shot_dir.y) > FLT_EPSILON) {
+            shot_dir.Normalize();
+            shot_dir.Rotate((rand() % 10) / 180.0f);
+            HumMaster()->attack_dir = shot_dir;
+            if (HumMaster()->curr_weapon->meta->NeedTrace()) {
+                HumMaster()->shot_target_id = enemy->entity_uniid;
+            } else {
+                HumMaster()->shot_target_id = 0;
+            }
+            HumMaster()->Shot();
         }
-        sender->Shot();
     }
 }
 
 void AndroidAI::UseSkill(Human* enemy)
 {
-    Human* sender = (Human*)owner;
-    if (!sender->CurrentSkillMeta()) {
+    if (!HumMaster()->CurrentSkillMeta()) {
         return;
     }
-    if (sender->CurrentSkillMeta()->i->skill_target() == kST_Self) {
-        sender->curr_skill_phase = 0;
-        sender->skill_target_id = sender->entity_uniid;
-        sender->skill_dir = a8::Vec2();
-        sender->skill_target_pos = sender->pos;
-        sender->skill_param1 = 0;
-        sender->playing_skill = false;
-        sender->DoSkill();
+    if (enemy->HasBuffEffect(kBET_Hide) ||
+        enemy->HasBuffEffect(kBET_Invincible) ||
+        enemy->dead) {
+        return;
+    }
+
+    if (HumMaster()->CurrentSkillMeta()->i->skill_target() == kST_Self) {
+        HumMaster()->curr_skill_phase = 0;
+        HumMaster()->skill_target_id = HumMaster()->entity_uniid;
+        HumMaster()->skill_dir = a8::Vec2();
+        HumMaster()->skill_target_pos = HumMaster()->pos;
+        HumMaster()->skill_param1 = 0;
+        HumMaster()->playing_skill = false;
+        HumMaster()->DoSkill();
     } else {
-        a8::Vec2 shot_dir = enemy->pos - sender->pos;
+        a8::Vec2 shot_dir = enemy->pos - HumMaster()->pos;
         if (std::abs(shot_dir.x) > FLT_EPSILON ||
             std::abs(shot_dir.y) > FLT_EPSILON) {
-            sender->curr_skill_phase = 0;
-            sender->skill_target_id = enemy->entity_uniid;
-            sender->skill_dir = shot_dir;
-            sender->skill_target_pos = enemy->pos;
-            sender->skill_param1 = 0;
-            sender->playing_skill = false;
-            sender->DoSkill();
+            HumMaster()->curr_skill_phase = 0;
+            HumMaster()->skill_target_id = enemy->entity_uniid;
+            HumMaster()->skill_dir = shot_dir;
+            HumMaster()->skill_target_pos = enemy->pos;
+            HumMaster()->skill_param1 = 0;
+            HumMaster()->playing_skill = false;
+            HumMaster()->DoSkill();
         }
     }
 }
diff --git a/server/gameserver/human.cc b/server/gameserver/human.cc
index a6b69ed..c9dbd67 100644
--- a/server/gameserver/human.cc
+++ b/server/gameserver/human.cc
@@ -17,6 +17,7 @@
 #include "app.h"
 #include "roommgr.h"
 #include "android.h"
+#include "android.ai.h"
 #include "gamelog.h"
 #include "typeconvert.h"
 #include "obstacle.h"
@@ -501,6 +502,12 @@ void Human::DecHP(float dec_hp, int killer_id, const std::string& killer_name, i
     last_attacker_name = killer_name;
     last_attacker_weapon_id = weapon_id;
     last_attacked_frameno = room->frameno;
+    if (entity_subtype == kEST_Android) {
+        Android* android = (Android*)this;
+        if (android->ai) {
+            android->ai->LockEnemy(last_attacker_id);
+        }
+    }
     SyncAroundPlayers();
 }
 
diff --git a/server/gameserver/human.h b/server/gameserver/human.h
index d8b4b61..2581983 100644
--- a/server/gameserver/human.h
+++ b/server/gameserver/human.h
@@ -264,4 +264,5 @@ private:
 
     friend class FrameMaker;
     friend class FrameEvent;
+    friend class AndroidAI;
 };
diff --git a/server/gameserver/metamgr.cc b/server/gameserver/metamgr.cc
index 5f70835..5139ee3 100755
--- a/server/gameserver/metamgr.cc
+++ b/server/gameserver/metamgr.cc
@@ -123,6 +123,14 @@ public:
             MetaMgr::Instance()->grass_invisible_time = MetaMgr::Instance()->GetSysParamAsInt("grass_invisible_time", 0.5f);
             MetaMgr::Instance()->grass_show_time = MetaMgr::Instance()->GetSysParamAsInt("grass_show_time", 0.5f);
             MetaMgr::Instance()->grass_invisible_time2 = MetaMgr::Instance()->GetSysParamAsInt("grass_invisible_time2", 2.0f);
+            MetaMgr::Instance()->robot_pursuit_range = MetaMgr::Instance()->
+                GetSysParamAsInt("robot_pursuit_range",
+                                 MetaMgr::Instance()->robot_pursuit_range
+                                 );
+            MetaMgr::Instance()->robot_attack_range = MetaMgr::Instance()->
+                GetSysParamAsInt("robot_attack_range",
+                                 MetaMgr::Instance()->robot_attack_range
+                                 );
             if (MetaMgr::Instance()->K < 0.01f) {
                 abort();
             }
diff --git a/server/gameserver/metamgr.h b/server/gameserver/metamgr.h
index 8cfc453..2b5d580 100755
--- a/server/gameserver/metamgr.h
+++ b/server/gameserver/metamgr.h
@@ -54,6 +54,8 @@ class MetaMgr : public a8::Singleton<MetaMgr>
     float grass_invisible_time = 0.5;
     float grass_show_time = 0.5f;
     float grass_invisible_time2 = 2.0f;
+    float robot_pursuit_range = 800.0f;
+    float robot_attack_range = 256.0f;
 
  private:
     MetaDataLoader* loader_ = nullptr;
diff --git a/server/tools/protobuild/metatable.proto b/server/tools/protobuild/metatable.proto
index 0856394..905040e 100755
--- a/server/tools/protobuild/metatable.proto
+++ b/server/tools/protobuild/metatable.proto
@@ -214,7 +214,8 @@ message Tank
     required int32 skill_id = 4;
     required string attr_origin = 5;
     required string attr_up = 6;
-    optional int32 type = 7;
+    required int32 type = 7;
+    required float atk_range = 8;
 }
 
 message TankSkin