diff --git a/Operation.md b/Operation.md
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+++ b/Operation.md
@@ -263,4 +263,6 @@
   ]
 }
 
-```
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+```
+
+##### utils [Utils](./Utils.md)
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diff --git a/Utils.md b/Utils.md
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--- /dev/null
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@@ -0,0 +1,81 @@
+#### Utils
+工具类
+
+##### parseXML: (xmlStr: string, options?: OpParseXMLOptions) => any
+op.utils.parseXML 用来解析 XML 字符串并返回一个 JSON 对象。
+
+参数说明：
+TODO
+示例代码：
+```javaScript
+exports.run = async (ctx, op) => {
+  const data = `
+  <oauth>
+    <data>
+      <list>
+        <name age="32">Tom</name>
+      </list>
+      <list>
+        <name age="28">Jerry</name>
+      </list>
+    </data>
+  </oauth>`;
+  return op.utils.parseXML(data, {
+    ignoreAttributes: false,
+    attributeNamePrefix : "X_",
+  });
+};
+```
+以上代码返回：
+```javaScript
+{
+  "oauth": {
+    "data": {
+      "list": [
+        {
+          "name": {
+            "#text": "Tom",
+            "X_age": "32",
+          }
+        },
+        {
+          "name": {
+            "#text": "Jerry",
+            "X_age": "28",
+          }
+        },
+      ]
+    }
+  }
+}
+
+```
+
+##### formatString: (data: any, from: string | undefined, to: string) => string
+op.utils.formatString 用以将字符串在 utf8、hex、base64 等格式之间进行转换。
+
+示例代码：
+TODO
+
+##### decodeSM4: (key: string, data: string, opts?: { mode?: string, iv?: string, inputEncoding?: string, outputEncoding?: string }) => string;
+##### encodeSM4: (key: string, data: string, opts?: { mode?: string, iv?: string, inputEncoding?: string, outputEncoding?: string }) => string;
+
+op.utils.encodeSM4 与 op.utils.decodeSM4 分别用以进行 sm4 的加解密。
+
+参数说明：
+TODO
+
+示例代码：
+```javaScript
+exports.run = async (ctx, op) => {
+  // 子账号加密示例
+  const secret = 'YOUR_SECRET';
+  const key = op.utils.formatString(secret, 'utf8', 'hex').slice(0, 32);
+  const data = 'YOUR_PASSWORD';
+  const encoded = '$SM4$' + op.utils.encodeSM4(key, data, { outputEncoding: 'base64' });
+  log(encoded);
+  // 子账号解密示例
+  const decoded = op.utils.decodeSM4(key, encoded.replace(/^\$SM4\$/, ''), { inputEncoding: 'base64', outputEncoding: 'utf8' });
+  log(decoded === data);
+};
+```
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