diff --git a/demo-album/lib/cos-wx-sdk-v5.js b/demo-album/lib/cos-wx-sdk-v5.js
index 89302e7..410667b 100644
--- a/demo-album/lib/cos-wx-sdk-v5.js
+++ b/demo-album/lib/cos-wx-sdk-v5.js
@@ -8904,53 +8904,41 @@ module.exports.init = function (COS, task) {
 /* 18 */
 /***/ (function(module, exports) {
 
-var obj2str = function (obj) {
-    var i, key, val;
-    var list = [];
-    var keyList = Object.keys(obj);
-    for (i = 0; i < keyList.length; i++) {
-        key = keyList[i];
-        val = obj[key] || '';
-        list.push(key + '=' + encodeURIComponent(val));
-    }
-    return list.join('&');
-};
+function camSafeUrlEncode(str) {
+  return encodeURIComponent(str)
+      .replace(/!/g, '%21')
+      .replace(/'/g, '%27')
+      .replace(/\(/g, '%28')
+      .replace(/\)/g, '%29')
+      .replace(/\*/g, '%2A');
+}
 
-var stringifyPrimitive = function(v) {
-  switch (typeof v) {
-      case 'string':
-          return v;
-      case 'boolean':
-          return v ? 'true' : 'false';
-      case 'number':
-          return isFinite(v) ? v : '';
-      default:
-          return '';
+function getObjectKeys(obj, forKey) {
+  var list = [];
+  for (var key in obj) {
+      if (obj.hasOwnProperty(key)) {
+          list.push(forKey ? camSafeUrlEncode(key).toLowerCase() : key);
+      }
   }
+  return list.sort(function (a, b) {
+      a = a.toLowerCase();
+      b = b.toLowerCase();
+      return a === b ? 0 : (a > b ? 1 : -1);
+  });
 };
 
-var queryStringify = function(obj, sep, eq, name) {
-  sep = sep || '&';
-  eq = eq || '=';
-  if (obj === null) {
-      obj = undefined;
-  }
-  if (typeof obj === 'object') {
-      return Object.keys(obj).map(function(k) {
-          var ks = encodeURIComponent(stringifyPrimitive(k)) + eq;
-          if (Array.isArray(obj[k])) {
-              return obj[k].map(function(v) {
-                  return ks + encodeURIComponent(stringifyPrimitive(v));
-              }).join(sep);
-          } else {
-              return ks + encodeURIComponent(stringifyPrimitive(obj[k]));
-          }
-      }).filter(Boolean).join(sep);
-
+var obj2str = function (obj) {
+  var i, key, val;
+  var list = [];
+  var keyList = getObjectKeys(obj);
+  for (i = 0; i < keyList.length; i++) {
+      key = keyList[i];
+      val = (obj[key] === undefined || obj[key] === null) ? '' : ('' + obj[key]);
+      key = camSafeUrlEncode(key).toLowerCase();
+      val = camSafeUrlEncode(val) || '';
+      list.push(key + '=' + val)
   }
-  if (!name) return '';
-  return encodeURIComponent(stringifyPrimitive(name)) + eq +
-      encodeURIComponent(stringifyPrimitive(obj));
+  return list.join('&');
 };
 
 var request = function (params, callback) {
@@ -9028,7 +9016,7 @@ var request = function (params, callback) {
             });
         });
     } else {
-        var qsStr = params.qs && queryStringify(params.qs) || '';
+        var qsStr = params.qs && obj2str(params.qs) || '';
         if (qsStr) {
             url += (url.indexOf('?') > -1 ? '&' : '?') + qsStr;
         }
diff --git a/demo/lib/cos-wx-sdk-v5.js b/demo/lib/cos-wx-sdk-v5.js
index 89302e7..410667b 100644
--- a/demo/lib/cos-wx-sdk-v5.js
+++ b/demo/lib/cos-wx-sdk-v5.js
@@ -8904,53 +8904,41 @@ module.exports.init = function (COS, task) {
 /* 18 */
 /***/ (function(module, exports) {
 
-var obj2str = function (obj) {
-    var i, key, val;
-    var list = [];
-    var keyList = Object.keys(obj);
-    for (i = 0; i < keyList.length; i++) {
-        key = keyList[i];
-        val = obj[key] || '';
-        list.push(key + '=' + encodeURIComponent(val));
-    }
-    return list.join('&');
-};
+function camSafeUrlEncode(str) {
+  return encodeURIComponent(str)
+      .replace(/!/g, '%21')
+      .replace(/'/g, '%27')
+      .replace(/\(/g, '%28')
+      .replace(/\)/g, '%29')
+      .replace(/\*/g, '%2A');
+}
 
-var stringifyPrimitive = function(v) {
-  switch (typeof v) {
-      case 'string':
-          return v;
-      case 'boolean':
-          return v ? 'true' : 'false';
-      case 'number':
-          return isFinite(v) ? v : '';
-      default:
-          return '';
+function getObjectKeys(obj, forKey) {
+  var list = [];
+  for (var key in obj) {
+      if (obj.hasOwnProperty(key)) {
+          list.push(forKey ? camSafeUrlEncode(key).toLowerCase() : key);
+      }
   }
+  return list.sort(function (a, b) {
+      a = a.toLowerCase();
+      b = b.toLowerCase();
+      return a === b ? 0 : (a > b ? 1 : -1);
+  });
 };
 
-var queryStringify = function(obj, sep, eq, name) {
-  sep = sep || '&';
-  eq = eq || '=';
-  if (obj === null) {
-      obj = undefined;
-  }
-  if (typeof obj === 'object') {
-      return Object.keys(obj).map(function(k) {
-          var ks = encodeURIComponent(stringifyPrimitive(k)) + eq;
-          if (Array.isArray(obj[k])) {
-              return obj[k].map(function(v) {
-                  return ks + encodeURIComponent(stringifyPrimitive(v));
-              }).join(sep);
-          } else {
-              return ks + encodeURIComponent(stringifyPrimitive(obj[k]));
-          }
-      }).filter(Boolean).join(sep);
-
+var obj2str = function (obj) {
+  var i, key, val;
+  var list = [];
+  var keyList = getObjectKeys(obj);
+  for (i = 0; i < keyList.length; i++) {
+      key = keyList[i];
+      val = (obj[key] === undefined || obj[key] === null) ? '' : ('' + obj[key]);
+      key = camSafeUrlEncode(key).toLowerCase();
+      val = camSafeUrlEncode(val) || '';
+      list.push(key + '=' + val)
   }
-  if (!name) return '';
-  return encodeURIComponent(stringifyPrimitive(name)) + eq +
-      encodeURIComponent(stringifyPrimitive(obj));
+  return list.join('&');
 };
 
 var request = function (params, callback) {
@@ -9028,7 +9016,7 @@ var request = function (params, callback) {
             });
         });
     } else {
-        var qsStr = params.qs && queryStringify(params.qs) || '';
+        var qsStr = params.qs && obj2str(params.qs) || '';
         if (qsStr) {
             url += (url.indexOf('?') > -1 ? '&' : '?') + qsStr;
         }
diff --git a/lib/request.js b/lib/request.js
index 378ca9a..60b2d9f 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -1,50 +1,38 @@
-var obj2str = function (obj) {
-    var i, key, val;
-    var list = [];
-    var keyList = Object.keys(obj);
-    for (i = 0; i < keyList.length; i++) {
-        key = keyList[i];
-        val = obj[key] || '';
-        list.push(key + '=' + encodeURIComponent(val));
-    }
-    return list.join('&');
-};
+function camSafeUrlEncode(str) {
+  return encodeURIComponent(str)
+      .replace(/!/g, '%21')
+      .replace(/'/g, '%27')
+      .replace(/\(/g, '%28')
+      .replace(/\)/g, '%29')
+      .replace(/\*/g, '%2A');
+}
 
-var stringifyPrimitive = function(v) {
-  switch (typeof v) {
-      case 'string':
-          return v;
-      case 'boolean':
-          return v ? 'true' : 'false';
-      case 'number':
-          return isFinite(v) ? v : '';
-      default:
-          return '';
+function getObjectKeys(obj, forKey) {
+  var list = [];
+  for (var key in obj) {
+      if (obj.hasOwnProperty(key)) {
+          list.push(forKey ? camSafeUrlEncode(key).toLowerCase() : key);
+      }
   }
+  return list.sort(function (a, b) {
+      a = a.toLowerCase();
+      b = b.toLowerCase();
+      return a === b ? 0 : (a > b ? 1 : -1);
+  });
 };
 
-var queryStringify = function(obj, sep, eq, name) {
-  sep = sep || '&';
-  eq = eq || '=';
-  if (obj === null) {
-      obj = undefined;
-  }
-  if (typeof obj === 'object') {
-      return Object.keys(obj).map(function(k) {
-          var ks = encodeURIComponent(stringifyPrimitive(k)) + eq;
-          if (Array.isArray(obj[k])) {
-              return obj[k].map(function(v) {
-                  return ks + encodeURIComponent(stringifyPrimitive(v));
-              }).join(sep);
-          } else {
-              return ks + encodeURIComponent(stringifyPrimitive(obj[k]));
-          }
-      }).filter(Boolean).join(sep);
-
+var obj2str = function (obj) {
+  var i, key, val;
+  var list = [];
+  var keyList = getObjectKeys(obj);
+  for (i = 0; i < keyList.length; i++) {
+      key = keyList[i];
+      val = (obj[key] === undefined || obj[key] === null) ? '' : ('' + obj[key]);
+      key = camSafeUrlEncode(key).toLowerCase();
+      val = camSafeUrlEncode(val) || '';
+      list.push(key + '=' + val)
   }
-  if (!name) return '';
-  return encodeURIComponent(stringifyPrimitive(name)) + eq +
-      encodeURIComponent(stringifyPrimitive(obj));
+  return list.join('&');
 };
 
 var request = function (params, callback) {
@@ -122,7 +110,7 @@ var request = function (params, callback) {
             });
         });
     } else {
-        var qsStr = params.qs && queryStringify(params.qs) || '';
+        var qsStr = params.qs && obj2str(params.qs) || '';
         if (qsStr) {
             url += (url.indexOf('?') > -1 ? '&' : '?') + qsStr;
         }