diff --git a/Editor/Commands/LinkGeneratorCommand.cs b/Editor/Commands/LinkGeneratorCommand.cs
index 1a5b7b7..c545ff5 100644
--- a/Editor/Commands/LinkGeneratorCommand.cs
+++ b/Editor/Commands/LinkGeneratorCommand.cs
@@ -28,7 +28,7 @@ namespace HybridCLR.Editor.Commands
             List<string> hotfixAssemblies = SettingsUtil.HotUpdateAssemblyNamesExcludePreserved;
 
             var analyzer = new Analyzer(MetaUtil.CreateHotUpdateAndAOTAssemblyResolver(target, hotfixAssemblies));
-            var refTypes = analyzer.CollectRefs(hotfixAssemblies, !ls.dontPreserveUnityEngineCoreTypesInLinkXml);
+            var refTypes = analyzer.CollectRefs(hotfixAssemblies);
 
             Debug.Log($"[LinkGeneratorCommand] hotfix assembly count:{hotfixAssemblies.Count}, ref type count:{refTypes.Count} output:{Application.dataPath}/{ls.outputLinkFile}");
             var linkXmlWriter = new LinkXmlWriter();
diff --git a/Editor/Link/Analyzer.cs b/Editor/Link/Analyzer.cs
index c2ca3e9..ffbb93d 100644
--- a/Editor/Link/Analyzer.cs
+++ b/Editor/Link/Analyzer.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Text;
@@ -22,48 +21,12 @@ namespace HybridCLR.Editor.Link
             _resolver = resolver;
         }
 
-
-        public HashSet<ITypeDefOrRef> CollectRefs(List<string> rootAssemblies, bool includeUnityEngineCoreTypes)
-        {
-            var typeRefs = new HashSet<ITypeDefOrRef>(TypeEqualityComparer.Instance);
-            CollectHotUpdateRefs(rootAssemblies, typeRefs);
-
-            if (includeUnityEngineCoreTypes)
-            {
-                CollectUnityEngineCoreTypes(typeRefs);
-            }
-            return typeRefs;
-        }
-
-        private void CollectUnityEngineCoreTypes(HashSet<ITypeDefOrRef> preservedTypes)
-        {
-            Debug.Log("CollectUnityEngineCoreTypes");
-            string unityEngineDllPath = $"{EditorApplication.applicationContentsPath}/Managed/UnityEngine";
-
-            var assCollector = new AssemblyCache(_resolver);
-            foreach (string unityEngineDll in Directory.GetFiles(unityEngineDllPath, "UnityEngine.*.dll", SearchOption.AllDirectories))
-            {
-                // because of bug of unity 2019.4.x, preserving types in this dll will cause crash in android build
-                if (unityEngineDll.EndsWith("UnityEngine.PerformanceReportingModule.dll", StringComparison.InvariantCulture))
-                {
-                    continue;
-                }
-                ModuleDefMD mod = assCollector.LoadModuleFromFileWithoutCache(unityEngineDll);
-                foreach (TypeDef type in mod.GetTypes())
-                {
-                    if (type.Methods.Any(m => m.IsInternalCall || m.IsPinvokeImpl))
-                    {
-                        preservedTypes.Add(type);
-                    }
-                }
-            }
-        }
-
-        public void CollectHotUpdateRefs(List<string> rootAssemblies, HashSet<ITypeDefOrRef> preservedTypes)
+        public HashSet<TypeRef> CollectRefs(List<string> rootAssemblies)
         {
             var assCollector = new AssemblyCache(_resolver);
             var rootAssemblyNames = new HashSet<string>(rootAssemblies);
 
+            var typeRefs = new HashSet<TypeRef>(TypeEqualityComparer.Instance);
             foreach (var rootAss in rootAssemblies)
             {
                 var dnAss = assCollector.LoadModule(rootAss, false);
@@ -76,10 +39,11 @@ namespace HybridCLR.Editor.Link
                     }
                     if (!rootAssemblyNames.Contains(type.DefinitionAssembly.Name.ToString()))
                     {
-                        preservedTypes.Add(type);
+                        typeRefs.Add(type);
                     }
                 }
             }
+            return typeRefs;
         }
     }
 }
diff --git a/Editor/Link/LinkXmlWriter.cs b/Editor/Link/LinkXmlWriter.cs
index 2667308..ab5d448 100644
--- a/Editor/Link/LinkXmlWriter.cs
+++ b/Editor/Link/LinkXmlWriter.cs
@@ -11,7 +11,7 @@ namespace HybridCLR.Editor.Link
 {
     internal class LinkXmlWriter
     {
-        public void Write(string outputLinkXmlFile, HashSet<ITypeDefOrRef> refTypes)
+        public void Write(string outputLinkXmlFile, HashSet<TypeRef> refTypes)
         {
             string parentDir = Directory.GetParent(outputLinkXmlFile).FullName;
             Directory.CreateDirectory(parentDir);
diff --git a/Editor/Meta/AssemblyCacheBase.cs b/Editor/Meta/AssemblyCacheBase.cs
index 4955223..04f2d15 100644
--- a/Editor/Meta/AssemblyCacheBase.cs
+++ b/Editor/Meta/AssemblyCacheBase.cs
@@ -71,13 +71,6 @@ namespace HybridCLR.Editor.Meta
             return mod;
         }
 
-        public ModuleDefMD LoadModuleFromFileWithoutCache(string dllPath)
-        {
-            ModuleDefMD mod = ModuleDefMD.Load(File.ReadAllBytes(dllPath), _modCtx);
-            mod.EnableTypeDefFindCache = true;
-            return mod;
-        }
-
         private void LoadNetStandard()
         {
             string netstandardDllPath = _assemblyPathResolver.ResolveAssembly("netstandard", false);
diff --git a/Editor/Settings/HybridCLRSettingProvider.cs b/Editor/Settings/HybridCLRSettingProvider.cs
index 47da29d..122187c 100644
--- a/Editor/Settings/HybridCLRSettingProvider.cs
+++ b/Editor/Settings/HybridCLRSettingProvider.cs
@@ -21,7 +21,6 @@ namespace HybridCLR.Editor.Settings
         private SerializedProperty _externalHotUpdateAssembliyDirs;
         private SerializedProperty _strippedAOTDllOutputRootDir;
         private SerializedProperty _patchAOTAssemblies;
-        private SerializedProperty _dontPreserveUnityEngineCoreTypesInLinkXml;
         private SerializedProperty _outputLinkFile;
         private SerializedProperty _outputAOTGenericReferenceFile;
         private SerializedProperty _maxGenericReferenceIteration;
@@ -52,7 +51,6 @@ namespace HybridCLR.Editor.Settings
             _externalHotUpdateAssembliyDirs = _serializedObject.FindProperty("externalHotUpdateAssembliyDirs");
             _strippedAOTDllOutputRootDir = _serializedObject.FindProperty("strippedAOTDllOutputRootDir");
             _patchAOTAssemblies = _serializedObject.FindProperty("patchAOTAssemblies");
-            _dontPreserveUnityEngineCoreTypesInLinkXml = _serializedObject.FindProperty("dontPreserveUnityEngineCoreTypesInLinkXml");
             _outputLinkFile = _serializedObject.FindProperty("outputLinkFile");
             _outputAOTGenericReferenceFile = _serializedObject.FindProperty("outputAOTGenericReferenceFile");
             _maxGenericReferenceIteration = _serializedObject.FindProperty("maxGenericReferenceIteration");
@@ -142,7 +140,6 @@ namespace HybridCLR.Editor.Settings
                 EditorGUILayout.PropertyField(_externalHotUpdateAssembliyDirs);
                 EditorGUILayout.PropertyField(_strippedAOTDllOutputRootDir);
                 EditorGUILayout.PropertyField(_patchAOTAssemblies);
-                EditorGUILayout.PropertyField(_dontPreserveUnityEngineCoreTypesInLinkXml);
                 EditorGUILayout.PropertyField(_outputLinkFile);
                 EditorGUILayout.PropertyField(_outputAOTGenericReferenceFile);
                 EditorGUILayout.PropertyField(_maxGenericReferenceIteration);
diff --git a/Editor/Settings/HybridCLRSettings.cs b/Editor/Settings/HybridCLRSettings.cs
index bcf3578..ef0e153 100644
--- a/Editor/Settings/HybridCLRSettings.cs
+++ b/Editor/Settings/HybridCLRSettings.cs
@@ -39,9 +39,6 @@ namespace HybridCLR.Editor.Settings
         [Tooltip("supplementary metadata assembly names(without .dll suffix)")]
         public string[] patchAOTAssemblies;
 
-        [Tooltip("don't preserve UnityEngine core types in link.xml")]
-        public bool dontPreserveUnityEngineCoreTypesInLinkXml;
-
         [Tooltip("output file of automatic generated link.xml by scanning hot update assemblies")]
         public string outputLinkFile = "HybridCLRGenerate/link.xml";