diff --git a/docs/README.md b/docs/README.md
index 00f1e61..5ae1cc5 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -120,7 +120,8 @@ title: Ruby SDK 使用指南 | 七牛云存储
                                     :expires_in         => expires_in_seconds,
                                     :callback_url       => callback_url,
                                     :callback_body_type => callback_body_type,
-                                    :customer           => end_user_id
+                                    :customer           => end_user_id,
+                                    :escape             => allow_upload_callback_api
 
 **参数**
 
@@ -139,6 +140,19 @@ title: Ruby SDK 使用指南 | 七牛云存储
 :customer
 : 可选，字符串类型（String），客户方终端用户（End User）的ID，该字段可以用来标示一个文件的属主，这在一些特殊场景下（比如给终端用户上传的图片打上名字水印）非常有用。
 
+:escape
+: 可选，数字类型，可选值 0 或者 1，缺省为 0 。值为 1 表示 callback 传递的自定义数据中允许存在转义符号 `$(VarExpression)`，参考 [VarExpression](/v3/api/words/#VarExpression)。
+
+当 `escape` 的值为 `1` 时，常见的转义语法如下：
+
+- 若 `callbackBodyType` 为 `application/json` 时，一个典型的自定义回调数据（[CallbackParams](/v3/api/io/#CallbackParams)）为：
+
+    `{foo: "bar", w: $(imageInfo.width), h: $(imageInfo.height), exif: $(exif)}`
+
+- 若 `callbackBodyType` 为 `application/x-www-form-urlencoded` 时，一个典型的自定义回调数据（[CallbackParams](/v3/api/io/#CallbackParams)）为：
+
+    `foo=bar&w=$(imageInfo.width)&h=$(imageInfo.height)&exif=$(exif)`
+
 **返回值**
 
 返回一个字符串类型（String）的用于上传文件用的临时授权 `upload_token`。
diff --git a/lib/qiniu/rs.rb b/lib/qiniu/rs.rb
index f826a44..0f70a8d 100755
--- a/lib/qiniu/rs.rb
+++ b/lib/qiniu/rs.rb
@@ -224,6 +224,7 @@ module Qiniu
         #token_obj.callback_url = opts[:callback_url]
         #token_obj.callback_body_type = opts[:callback_body_type]
         #token_obj.customer = opts[:customer]
+        #token_obj.escape = opts[:escape]
         token_obj.generate_token
       end
 
diff --git a/lib/qiniu/rs/version.rb b/lib/qiniu/rs/version.rb
index eb073b7..03918d0 100755
--- a/lib/qiniu/rs/version.rb
+++ b/lib/qiniu/rs/version.rb
@@ -5,7 +5,7 @@ module Qiniu
     module Version
       MAJOR = 3
       MINOR = 1
-      PATCH = 0
+      PATCH = 1
       # Returns a version string by joining <tt>MAJOR</tt>, <tt>MINOR</tt>, and <tt>PATCH</tt> with <tt>'.'</tt>
       #
       # Example
diff --git a/lib/qiniu/tokens/upload_token.rb b/lib/qiniu/tokens/upload_token.rb
index 5fb22b3..bb13af4 100755
--- a/lib/qiniu/tokens/upload_token.rb
+++ b/lib/qiniu/tokens/upload_token.rb
@@ -10,7 +10,7 @@ module Qiniu
 
         include Utils
 
-        attr_accessor :scope, :expires_in, :callback_url, :callback_body_type, :customer
+        attr_accessor :scope, :expires_in, :callback_url, :callback_body_type, :customer, :escape
 
         def initialize(opts = {})
           @scope = opts[:scope]
@@ -18,6 +18,7 @@ module Qiniu
           @callback_url = opts[:callback_url]
           @callback_body_type = opts[:callback_body_type]
           @customer = opts[:customer]
+          @escape = opts[:escape]
         end
 
         def generate_signature
@@ -25,6 +26,7 @@ module Qiniu
           params[:callbackUrl] = @callback_url if !@callback_url.nil? && !@callback_url.empty?
           params[:callbackBodyType] = @callback_body_type if !@callback_body_type.nil? && !@callback_body_type.empty?
           params[:customer] = @customer if !@customer.nil? && !@customer.empty?
+          params[:escape] = 1 if @escape == 1 || @escape == true
           urlsafe_base64_encode(params.to_json)
         end
 
diff --git a/spec/qiniu/rs_spec.rb b/spec/qiniu/rs_spec.rb
index 8204b18..a5f3a27 100755
--- a/spec/qiniu/rs_spec.rb
+++ b/spec/qiniu/rs_spec.rb
@@ -116,7 +116,7 @@ module Qiniu
 
     context ".upload_file" do
       it "should works" do
-        uptoken_opts = {:scope => @bucket}
+        uptoken_opts = {:scope => @bucket, :escape => 0}
         upload_opts = {
           :uptoken => Qiniu::RS.generate_upload_token(uptoken_opts),
           :file => __FILE__,
@@ -137,7 +137,7 @@ module Qiniu
         File.open(localfile, "w"){|f| 5242888.times{f.write(Random.rand(9).to_s)}}
         key = Digest::SHA1.hexdigest(localfile+Time.now.to_s)
         # generate the upload token
-        uptoken_opts = {:scope => @bucket, :expires_in => 3600, :customer => "awhy.xu@gmail.com"}
+        uptoken_opts = {:scope => @bucket, :expires_in => 3600, :customer => "awhy.xu@gmail.com", :escape => 0}
         uptoken = Qiniu::RS.generate_upload_token(uptoken_opts)
         # uploading
         upload_opts = {
@@ -311,7 +311,7 @@ module Qiniu
 
     context ".generate_upload_token" do
       it "should works" do
-        data = Qiniu::RS.generate_upload_token({:scope => 'test_bucket', :expires_in => 3600})
+        data = Qiniu::RS.generate_upload_token({:scope => 'test_bucket', :expires_in => 3600, :escape => 0})
         data.should_not be_empty
         puts data.inspect
       end