 With the failure of non-surgical strategies, bariatric surgery has emerged as the most effective therapeutic option for the treatment of severe obesity. From the beginning, there are a lot of types of operation which have been created and then been abandoned. Now, the most common is Roux-en-Y gastric bypass, sleeve gastrectomy SG, gastric banding, and biliopancreatic diversion. In recent years, the international status of SG surgery gradually went up. Since 2013, SG has been recommended as the preferred option of bariatric surgery by the American Weight Loss Society. However, the underlying mechanism of SG procedure is not fully clear. 