diff --git a/MJExtension.podspec b/MJExtension.podspec
index f312ea72..d7b49627 100644
--- a/MJExtension.podspec
+++ b/MJExtension.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "MJExtension"
-  s.version      = "3.0.11"
+  s.version      = "3.0.12"
   s.ios.deployment_target = '6.0'
   s.osx.deployment_target = '10.8'
   s.summary      = "A fast and convenient conversion between JSON and model"
diff --git a/MJExtension/MJPropertyType.m b/MJExtension/MJPropertyType.m
index b78b2028..384beba5 100755
--- a/MJExtension/MJPropertyType.m
+++ b/MJExtension/MJPropertyType.m
@@ -22,14 +22,15 @@ + (void)initialize
 + (instancetype)cachedTypeWithCode:(NSString *)code
 {
     MJExtensionAssertParamNotNil2(code, nil);
-    
-    MJPropertyType *type = types_[code];
-    if (type == nil) {
-        type = [[self alloc] init];
-        type.code = code;
-        types_[code] = type;
+    @synchronized (self) {
+        MJPropertyType *type = types_[code];
+        if (type == nil) {
+            type = [[self alloc] init];
+            type.code = code;
+            types_[code] = type;
+        }
+        return type;
     }
-    return type;
 }
 
 #pragma mark - 公共方法
diff --git a/MJExtension/NSObject+MJClass.m b/MJExtension/NSObject+MJClass.m
index 789b9a89..46447a86 100644
--- a/MJExtension/NSObject+MJClass.m
+++ b/MJExtension/NSObject+MJClass.m
@@ -34,11 +34,13 @@ + (void)load
 
 + (NSMutableDictionary *)dictForKey:(const void *)key
 {
-    if (key == &MJAllowedPropertyNamesKey) return allowedPropertyNamesDict_;
-    if (key == &MJIgnoredPropertyNamesKey) return ignoredPropertyNamesDict_;
-    if (key == &MJAllowedCodingPropertyNamesKey) return allowedCodingPropertyNamesDict_;
-    if (key == &MJIgnoredCodingPropertyNamesKey) return ignoredCodingPropertyNamesDict_;
-    return nil;
+    @synchronized (self) {
+        if (key == &MJAllowedPropertyNamesKey) return allowedPropertyNamesDict_;
+        if (key == &MJIgnoredPropertyNamesKey) return ignoredPropertyNamesDict_;
+        if (key == &MJAllowedCodingPropertyNamesKey) return allowedCodingPropertyNamesDict_;
+        if (key == &MJIgnoredCodingPropertyNamesKey) return ignoredCodingPropertyNamesDict_;
+        return nil;
+    }
 }
 
 + (void)mj_enumerateClasses:(MJClassesEnumeration)enumeration
diff --git a/MJExtension/NSObject+MJProperty.m b/MJExtension/NSObject+MJProperty.m
index fd7197a0..2314c460 100644
--- a/MJExtension/NSObject+MJProperty.m
+++ b/MJExtension/NSObject+MJProperty.m
@@ -44,12 +44,14 @@ + (void)load
 
 + (NSMutableDictionary *)dictForKey:(const void *)key
 {
-    if (key == &MJReplacedKeyFromPropertyNameKey) return replacedKeyFromPropertyNameDict_;
-    if (key == &MJReplacedKeyFromPropertyName121Key) return replacedKeyFromPropertyName121Dict_;
-    if (key == &MJNewValueFromOldValueKey) return newValueFromOldValueDict_;
-    if (key == &MJObjectClassInArrayKey) return objectClassInArrayDict_;
-    if (key == &MJCachedPropertiesKey) return cachedPropertiesDict_;
-    return nil;
+    @synchronized (self) {
+        if (key == &MJReplacedKeyFromPropertyNameKey) return replacedKeyFromPropertyNameDict_;
+        if (key == &MJReplacedKeyFromPropertyName121Key) return replacedKeyFromPropertyName121Dict_;
+        if (key == &MJNewValueFromOldValueKey) return newValueFromOldValueDict_;
+        if (key == &MJObjectClassInArrayKey) return objectClassInArrayDict_;
+        if (key == &MJCachedPropertiesKey) return cachedPropertiesDict_;
+        return nil;
+    }
 }
 
 #pragma mark - --私有方法--