diff --git a/Apewer/UnparallelAttribute.cs b/Apewer/UnparallelAttribute.cs
new file mode 100644
index 0000000..d5b39a2
--- /dev/null
+++ b/Apewer/UnparallelAttribute.cs
@@ -0,0 +1,16 @@
+using System;
+
+namespace Apewer
+{
+
+    /// <summary>表示方法不可并行。</summary>
+    [AttributeUsage(AttributeTargets.Method)]
+    public sealed class UnparallelAttribute : Attribute
+    {
+
+        /// <summary></summary>
+        public static implicit operator bool(UnparallelAttribute unparallel) => unparallel != null;
+
+    }
+
+}
diff --git a/Apewer/Web/ApiAction.cs b/Apewer/Web/ApiAction.cs
index 26db784..8f88482 100644
--- a/Apewer/Web/ApiAction.cs
+++ b/Apewer/Web/ApiAction.cs
@@ -2,7 +2,6 @@
 using System;
 using System.Collections.Generic;
 using System.Reflection;
-using System.Text;
 
 namespace Apewer.Web
 {
@@ -19,6 +18,7 @@ namespace Apewer.Web
         string _path = null;
         HttpMethod[] _methods = null;
         ApiParameter[] _parameters = null;
+        UnparallelAttribute _unparallel = null;
 
         #endregion
 
@@ -55,6 +55,9 @@ namespace Apewer.Web
             }
         }
 
+        /// <summary>不可并行。</summary>
+        public UnparallelAttribute Unparallel { get => _unparallel; }
+
         /// <summary>生成 JSON 实例。</summary>
         public Json ToJson() => ToJson(null);
 
@@ -109,9 +112,10 @@ namespace Apewer.Web
         /// <param name="path">URL 路径。</param>
         /// <param name="methods">HTTP 方法。</param>
         /// <param name="parameters">参数。</param>
+        /// <param name="unparallel">不可并行。</param>
         /// <exception cref="ArgumentNullException" />
         /// <exception cref="ArgumentException" />
-        ApiAction(Type type, MethodInfo method, string path, HttpMethod[] methods, ApiParameter[] parameters)
+        ApiAction(Type type, MethodInfo method, string path, HttpMethod[] methods, ApiParameter[] parameters, UnparallelAttribute unparallel)
         {
             if (type == null) throw new ArgumentNullException(nameof(type));
             if (method == null) throw new ArgumentNullException(nameof(method));
@@ -128,6 +132,7 @@ namespace Apewer.Web
             _path = path;
             _methods = methods;
             _parameters = parameters;
+            _unparallel = unparallel;
         }
 
         /// <summary>解析控制器类型，获取 API 活动。</summary>
@@ -213,7 +218,10 @@ namespace Apewer.Web
                     parameters.Add(parameter);
                 }
 
-                var action = new ApiAction(type, method, path, httpMethods.ToArray(), parameters.ToArray());
+                // 不可并行
+                var unparallel = RuntimeUtility.GetAttribute<UnparallelAttribute>(method);
+
+                var action = new ApiAction(type, method, path, httpMethods.ToArray(), parameters.ToArray(), unparallel);
                 actions.Add(action);
             }
 
diff --git a/Apewer/Web/ApiProcessor.cs b/Apewer/Web/ApiProcessor.cs
index cf0d26f..dec3352 100644
--- a/Apewer/Web/ApiProcessor.cs
+++ b/Apewer/Web/ApiProcessor.cs
@@ -452,10 +452,7 @@ namespace Apewer.Web
                 if (initializer != null)
                 {
                     var @continue = true;
-                    UnparallelLocker.InLock(GetUnparallelKey(controller.GetType()), () =>
-                    {
-                        @continue = initializer.Invoke(controller);
-                    });
+                    @continue = initializer.Invoke(controller);
                     if (!@continue) return;
                 }
 
@@ -466,10 +463,7 @@ namespace Apewer.Web
                 {
                     // 调用 API，获取返回值。
                     _context.Controller = controller;
-                    UnparallelLocker.InLock(GetUnparallelKey(function.Method), () =>
-                    {
-                        Invoke(_context, function.Method, function.Parameters);
-                    });
+                    Invoke(_context, function.Method, function.Parameters);
                 }
                 else
                 {
@@ -477,11 +471,8 @@ namespace Apewer.Web
                     var @default = ApiUtility.GetDefault(controller);
                     if (@default != null)
                     {
-                        UnparallelLocker.InLock(GetUnparallelKey(controller.GetType()), () =>
-                        {
-                            @default.Invoke(controller);
-                            return;
-                        });
+                        @default.Invoke(controller);
+                        return;
                     }
 
                     // 没有执行任何 Function，尝试枚举。
diff --git a/Apewer/Web/ApiUtility.cs b/Apewer/Web/ApiUtility.cs
index 79356d8..2c01b9c 100644
--- a/Apewer/Web/ApiUtility.cs
+++ b/Apewer/Web/ApiUtility.cs
@@ -736,6 +736,14 @@ namespace Apewer.Web
             {
                 try
                 {
+                    if (exception is IApiException apiException)
+                    {
+                        if (!string.IsNullOrEmpty(apiException.Status))
+                        {
+                            response.Status = apiException.Status.ToLower();
+                        }
+                    }
+
                     if (setData)
                     {
                         var json = ToJson(exception);