diff --git a/encodings/index.js b/encodings/index.js
index d95c2441..4a46426a 100644
--- a/encodings/index.js
+++ b/encodings/index.js
@@ -6,7 +6,8 @@ var modules = [
     require("./internal"),
     require("./utf32"),
     require("./utf16"),
-    require("./utf7"),
+    // require("./utf7"),
+    // require("../externalEcods/utf7"),
     require("./sbcs-codec"),
     require("./sbcs-data"),
     require("./sbcs-data-generated"),
diff --git a/lib/index.js b/lib/index.js
index 657701c3..deb7749d 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -52,6 +52,26 @@ iconv.encodingExists = function encodingExists(enc) {
     }
 }
 
+/**
+ * input an encodes
+ * @param {string} enc 
+ * @param {string} src 
+ * @param {boolean} replace override existing encodings/aliases
+ */
+iconv.addEncoding = function (enc,src, replace) {
+  console.log('added');
+  var hasExt = iconv.encodingExists(enc)
+  if (!hasExt || (hasExt && replace)) {
+    // iconv.encodings = {}
+    var exEcods = require(src)
+    for (const key in exEcods) {
+      if (Object.hasOwnProperty.call(exEcods, key)) {
+        iconv.encodings[key] = exEcods[key];
+      }
+    }
+  }
+}
+
 // Legacy aliases to convert functions
 iconv.toEncoding = iconv.encode;
 iconv.fromEncoding = iconv.decode;
diff --git a/test/utf7-test.js b/test/utf7-test.js
index 37d7cfaf..99e4cbdb 100644
--- a/test/utf7-test.js
+++ b/test/utf7-test.js
@@ -5,6 +5,10 @@ var assert = require('assert'),
 // These tests are mostly from https://github.com/kkaefer/utf7
 // In case of ambiguity, we do the same as iconv. For example, we encode "optional direct" characters, but leave spaces and \n\r\t as-is.
 
+// now,utf7 is a external encodingExists,we need add
+if (!iconv.encodingExists('utf7')) {
+  iconv.addEncoding('utf7',"../externalEcods/utf7")
+}
 describe("UTF-7 codec", function() {
     it("encodes correctly", function() {
         // Examples from RFC 2152.