json的key值为\u5317\u4eac这种编码，怎么获取？

　var json={"memo":"{\"\\u57ce\\u5e02\":\"\\u5317\\u4eac\",\"\\u8054\\u7cfb\\u7535\\u8bdd\":\"999\",\"\\u5730\\u5740\":\"\\u8bf4\\u8bf4\\u51e0\\u53f7\\u653e\\u5047\\u554a\",\"\\u90ae\\u7bb1\":\"\",\"\\u7b80\\u4ecb\":\"\\u8bf4\\u8bf4\\u51e0\\u53f7\\u653e\\u5047\\u554a\",\"\\u7ecf\\u8425\\u8303\\u56f4\":\"\\u5a5a\\u5e86\"}","name":"\u5a5a\u793c\u7eaa","user_id":24,"logo_path":"merchant_logo/101376049270.jpg","license_path":"image_license/101376049270.jpg","city":"\u5317\u4eac","email":"","pid":1};json.memo=eval('('+json.memo+')');alert(json.memo['简介']);alert(JSON.stringify(json.memo));这全是英文简答，我费了很大功夫。