diff --git a/cocos/2d/CCSpriteFrameCache.cpp b/cocos/2d/CCSpriteFrameCache.cpp
index 334fc4f805d2..232ad0c1c71b 100644
--- a/cocos/2d/CCSpriteFrameCache.cpp
+++ b/cocos/2d/CCSpriteFrameCache.cpp
@@ -757,7 +757,7 @@ bool SpriteFrameCache::PlistFramesCache::erasePlistIndex(const std::string &plis
     if (it == _indexPlist2Frames.end()) return false;
 
     auto &frames = it->second;
-    for (auto f : frames)
+    for (const auto& f : frames)
     {
         // !!do not!! call `_spriteFrames.erase(f);` to erase SpriteFrame
         // only erase index here
diff --git a/cocos/2d/CCTMXXMLParser.cpp b/cocos/2d/CCTMXXMLParser.cpp
index 06a38fc271a5..632ce0f9ecea 100644
--- a/cocos/2d/CCTMXXMLParser.cpp
+++ b/cocos/2d/CCTMXXMLParser.cpp
@@ -752,7 +752,7 @@ void TMXMapInfo::endElement(void* /*ctx*/, const char *name)
             }
 
             uint32_t* bufferPtr = reinterpret_cast<uint32_t*>(buffer);
-            for(auto gidToken : gidTokens) {
+            for(const auto& gidToken : gidTokens) {
                 auto tileGid = (uint32_t)strtoul(gidToken.c_str(), nullptr, 10);
                 *bufferPtr = tileGid;
                 bufferPtr++;
diff --git a/cocos/3d/CCAnimate3D.cpp b/cocos/3d/CCAnimate3D.cpp
index 6074c8b49c54..dd72df1463c6 100644
--- a/cocos/3d/CCAnimate3D.cpp
+++ b/cocos/3d/CCAnimate3D.cpp
@@ -392,7 +392,7 @@ void Animate3D::update(float t)
                     float prekeyTime = lastTime * getDuration() * _frameRate;
                     float keyTime = t * getDuration() * _frameRate;
                     std::vector<Animate3DDisplayedEventInfo*> eventInfos;
-                    for (auto keyFrame : _keyFrameUserInfos)
+                    for (const auto& keyFrame : _keyFrameUserInfos)
                     {
                         if ((!_playReverse && keyFrame.first >= prekeyTime && keyFrame.first < keyTime)
                             || (_playReverse && keyFrame.first >= keyTime && keyFrame.first < prekeyTime))
diff --git a/cocos/3d/CCAnimation3D.cpp b/cocos/3d/CCAnimation3D.cpp
index 4ee4eefa18d4..f8b75a9601d0 100644
--- a/cocos/3d/CCAnimation3D.cpp
+++ b/cocos/3d/CCAnimation3D.cpp
@@ -87,8 +87,9 @@ Animation3D::Animation3D()
 
 Animation3D::~Animation3D()
 {
-    for (auto itor : _boneCurves) {
-        CC_SAFE_DELETE(itor.second);
+    for (const auto& itor : _boneCurves) {
+        Curve* curve = itor.second;
+        CC_SAFE_DELETE(curve);
     }
 }
 
diff --git a/cocos/3d/CCBundle3D.cpp b/cocos/3d/CCBundle3D.cpp
index baf381f88038..0420d75d70b2 100644
--- a/cocos/3d/CCBundle3D.cpp
+++ b/cocos/3d/CCBundle3D.cpp
@@ -2210,7 +2210,7 @@ std::vector<Vec3> Bundle3D::getTrianglesList(const std::string& path)
     Bundle3D::destroyBundle(bundle);
     for (auto iter : meshs.meshDatas){
         int preVertexSize = iter->getPerVertexSize() / sizeof(float);
-        for (auto indexArray : iter->subMeshIndices){
+        for (const auto& indexArray : iter->subMeshIndices){
             for (auto i : indexArray){
                 trianglesList.push_back(Vec3(iter->vertex[i * preVertexSize], iter->vertex[i * preVertexSize + 1], iter->vertex[i * preVertexSize + 2]));
             }
diff --git a/cocos/3d/CCSkeleton3D.cpp b/cocos/3d/CCSkeleton3D.cpp
index e8595cc13b14..267ba2bff877 100644
--- a/cocos/3d/CCSkeleton3D.cpp
+++ b/cocos/3d/CCSkeleton3D.cpp
@@ -202,7 +202,7 @@ void Bone3D::updateLocalMat()
         Quaternion quat(Quaternion::ZERO);
         
         float total = 0.f;
-        for (auto it: _blendStates) {
+        for (const auto& it: _blendStates) {
             total += it.weight;
         }
         if (total)
diff --git a/cocos/3d/CCTerrain.cpp b/cocos/3d/CCTerrain.cpp
index 20c35b58b35d..19335b2acc8d 100644
--- a/cocos/3d/CCTerrain.cpp
+++ b/cocos/3d/CCTerrain.cpp
@@ -1335,7 +1335,7 @@ bool Terrain::Chunk::getIntersectPointWithRay(const Ray& ray, Vec3& intersectPoi
 
     float minDist = FLT_MAX;
     bool isFind = false;
-    for (auto triangle : _trianglesList)
+    for (const auto& triangle : _trianglesList)
     {
         Vec3 p;
         if (triangle.getIntersectPoint(ray, p))
diff --git a/cocos/editor-support/cocostudio/ActionTimeline/CCActionTimeline.cpp b/cocos/editor-support/cocostudio/ActionTimeline/CCActionTimeline.cpp
index 6d749a8dc2bd..a43e6fe8eb86 100644
--- a/cocos/editor-support/cocostudio/ActionTimeline/CCActionTimeline.cpp
+++ b/cocos/editor-support/cocostudio/ActionTimeline/CCActionTimeline.cpp
@@ -176,7 +176,7 @@ ActionTimeline* ActionTimeline::clone() const
     newAction->setDuration(_duration);
     newAction->setTimeSpeed(_timeSpeed);
 
-    for (auto timelines : _timelineMap)
+    for (const auto& timelines : _timelineMap)
     {
         for(auto timeline : timelines.second)
         {      
@@ -185,7 +185,7 @@ ActionTimeline* ActionTimeline::clone() const
         }
     }
     
-    for( auto info : _animationInfos)
+    for(const auto& info : _animationInfos)
     {
         newAction->addAnimationInfo(info.second);
     }
@@ -416,7 +416,7 @@ void ActionTimeline::emitFrameEndCallFuncs(int frameIndex)
     if (clipEndCallsIter != _frameEndCallFuncs.end())
     {
         auto clipEndCalls = (*clipEndCallsIter).second;
-        for (auto call : clipEndCalls)
+        for (const auto& call : clipEndCalls)
             (call).second();
     }
 }
diff --git a/cocos/editor-support/cocostudio/CCArmatureDataManager.cpp b/cocos/editor-support/cocostudio/CCArmatureDataManager.cpp
index b91903ce6010..88e7539b8017 100644
--- a/cocos/editor-support/cocostudio/CCArmatureDataManager.cpp
+++ b/cocos/editor-support/cocostudio/CCArmatureDataManager.cpp
@@ -95,22 +95,22 @@ void ArmatureDataManager::removeArmatureFileInfo(const std::string& configFilePa
 {
     if (RelativeData *data = getRelativeData(configFilePath))
     {
-        for (std::string str : data->armatures)
+        for (const std::string& str : data->armatures)
         {
             removeArmatureData(str);
         }
 
-        for (std::string str : data->animations)
+        for (const std::string& str : data->animations)
         {
             removeAnimationData(str);
         }
 
-        for (std::string str : data->textures)
+        for (const std::string& str : data->textures)
         {
             removeTextureData(str);
         }
 
-        for (std::string str : data->plistFiles)
+        for (const std::string& str : data->plistFiles)
         {
             SpriteFrameCacheHelper::getInstance()->removeSpriteFrameFromFile(str);
         }
diff --git a/cocos/physics/CCPhysicsJoint.cpp b/cocos/physics/CCPhysicsJoint.cpp
index afa1cf98a623..8ab7457ae51d 100644
--- a/cocos/physics/CCPhysicsJoint.cpp
+++ b/cocos/physics/CCPhysicsJoint.cpp
@@ -180,7 +180,7 @@ bool PhysicsJoint::initJoint()
 
 void PhysicsJoint::flushDelayTasks()
 {
-    for (auto tsk : _delayTasks)
+    for (const auto& tsk : _delayTasks)
     {
         tsk();
     }
diff --git a/cocos/scripting/js-bindings/manual/js_manual_conversions.cpp b/cocos/scripting/js-bindings/manual/js_manual_conversions.cpp
index 7e32b83745b6..607ef7c015a2 100644
--- a/cocos/scripting/js-bindings/manual/js_manual_conversions.cpp
+++ b/cocos/scripting/js-bindings/manual/js_manual_conversions.cpp
@@ -2730,7 +2730,7 @@ jsval std_vector_string_to_jsval( JSContext *cx, const std::vector<std::string>&
     JS::RootedObject jsretArr(cx, JS_NewArrayObject(cx, v.size()));
 
     int i = 0;
-    for (const std::string obj : v)
+    for (const std::string& obj : v)
     {
         JS::RootedValue arrElement(cx);
         arrElement = std_string_to_jsval(cx, obj);
diff --git a/cocos/scripting/lua-bindings/manual/physics3d/lua_cocos2dx_physics3d_manual.cpp b/cocos/scripting/lua-bindings/manual/physics3d/lua_cocos2dx_physics3d_manual.cpp
index c7db1215b07a..147edefd0d30 100644
--- a/cocos/scripting/lua-bindings/manual/physics3d/lua_cocos2dx_physics3d_manual.cpp
+++ b/cocos/scripting/lua-bindings/manual/physics3d/lua_cocos2dx_physics3d_manual.cpp
@@ -760,7 +760,7 @@ int lua_cocos2dx_physics3d_Physics3DObject_setCollisionCallback(lua_State* L)
             {
                 int vecIndex = 1;
                 lua_newtable(L);
-                for (auto value : ci.collisionPointList)
+                for (const auto& value : ci.collisionPointList)
                 {
                     lua_pushnumber(L, vecIndex);
                     CollisionPoint_to_luaval(L, value);
diff --git a/extensions/Particle3D/PU/CCPURibbonTrailRender.cpp b/extensions/Particle3D/PU/CCPURibbonTrailRender.cpp
index 55adc27241da..0b23ad4120a5 100644
--- a/extensions/Particle3D/PU/CCPURibbonTrailRender.cpp
+++ b/extensions/Particle3D/PU/CCPURibbonTrailRender.cpp
@@ -73,7 +73,7 @@ void PURibbonTrailRender::render( Renderer* renderer, const Mat4 &transform, Par
 
     const PUParticleSystem3D::ParticlePoolMap &emitterPool = static_cast<PUParticleSystem3D *>(particleSystem)->getEmittedEmitterParticlePool();
     if (!emitterPool.empty()){
-        for (auto iter : emitterPool){
+        for (const auto& iter : emitterPool){
             updateParticles(iter.second);
             needDraw = true;
         }
@@ -81,7 +81,7 @@ void PURibbonTrailRender::render( Renderer* renderer, const Mat4 &transform, Par
 
     const PUParticleSystem3D::ParticlePoolMap &systemPool = static_cast<PUParticleSystem3D *>(particleSystem)->getEmittedSystemParticlePool();
     if (!systemPool.empty()){
-        for (auto iter : systemPool){
+        for (const auto& iter : systemPool){
             updateParticles(iter.second);
             needDraw = true;
         }
diff --git a/extensions/Particle3D/PU/CCPUScriptCompiler.cpp b/extensions/Particle3D/PU/CCPUScriptCompiler.cpp
index c17cc1f2a42c..e06e6d75e394 100644
--- a/extensions/Particle3D/PU/CCPUScriptCompiler.cpp
+++ b/extensions/Particle3D/PU/CCPUScriptCompiler.cpp
@@ -185,7 +185,7 @@ PUScriptCompiler::PUScriptCompiler():_current(nullptr),_nodes(nullptr), _PUParti
 }
 PUScriptCompiler::~PUScriptCompiler()
 {
-    for (auto iter : _compiledScripts){
+    for (const auto& iter : _compiledScripts){
         for (auto miter : iter.second){
             delete miter;
         }
diff --git a/extensions/assets-manager/AssetsManagerEx.cpp b/extensions/assets-manager/AssetsManagerEx.cpp
index 42f6117b896b..fe4f9230fb89 100644
--- a/extensions/assets-manager/AssetsManagerEx.cpp
+++ b/extensions/assets-manager/AssetsManagerEx.cpp
@@ -224,7 +224,7 @@ void AssetsManagerEx::loadLocalManifest(const std::string& /*manifestUrl*/)
     {
         std::vector<std::string> cacheSearchPaths = cachedManifest->getSearchPaths();
         std::vector<std::string> trimmedPaths = searchPaths;
-        for (auto path : cacheSearchPaths)
+        for (const auto& path : cacheSearchPaths)
         {
             const auto pos = std::find(trimmedPaths.begin(), trimmedPaths.end(), path);
             if (pos != trimmedPaths.end())
@@ -1133,7 +1133,7 @@ void AssetsManagerEx::destroyDownloadedVersion()
 void AssetsManagerEx::batchDownload()
 {
     _queue.clear();
-    for(auto iter : _downloadUnits)
+    for(const auto& iter : _downloadUnits)
     {
         const DownloadUnit& unit = iter.second;
         if (unit.size > 0)
diff --git a/tests/lua-tests/project/Classes/lua_test_bindings.cpp b/tests/lua-tests/project/Classes/lua_test_bindings.cpp
index 955a68fb08a8..cce23f87332d 100644
--- a/tests/lua-tests/project/Classes/lua_test_bindings.cpp
+++ b/tests/lua-tests/project/Classes/lua_test_bindings.cpp
@@ -339,7 +339,7 @@ ValueTypeJudgeInTable* ValueTypeJudgeInTable::create(ValueMap valueMap)
     }
     
     int index = 0;
-    for (auto iter : valueMap)
+    for (const auto& iter : valueMap)
     {
         Value::Type type = iter.second.getType();
         if (type == Value::Type::STRING) {