With the development of social economy and the improvement of material living standard, the incidence of obesity has increased significantly. 10 years from 1992 to 2002, the overweight rate and obesity rate of Chinese residents increased by 38.6% and 80.6% respectively. the incidence of obesity in China was nearly 25% in 2002, and the trend is rapidly increasing. Obesity is associated with the onset of many diseases such as type 2 diabetes, hypertension, coronary heart disease, dyslipidemia, sleep apnea and tumors. Morbid obesity has become a serious public health problem. The prevention and intervention treatment of obesity has become a hot spot of international research. Current treatment modalities for obesity include diet control, exercise, drugs and surgery. The US Centers for Disease Control reports that even with the current forms of intervention, the incidence of obesity will increase by 39% in 2010. Diet control and exercise are only effective for overweight and mildly obese individuals, with weight loss typically at 5-10% and weight regain at 5 years of almost 100%. Weight loss medication usually requires a two-year cycle and can achieve weight loss of 5-10% in 60-70% of obese individuals. Abdominal liposuction, on the other hand, does not significantly improve the metabolic abnormalities associated with obesity. For patients with severe morbid obesity, neither behavioral modification nor pharmacological treatment has significant efficacy. Gastrointestinal bariatric surgery is an effective treatment for morbid obesity. Studies have shown that gastrointestinal bariatric surgery in severely obese patients can lead to clinical remission in 60-80% of patients with type 2 diabetes, with better outcomes when the disease is in its early stages. With improved surgical safety and the implementation of minimally invasive procedures, the research evidence for gastrointestinal bariatric surgery for the treatment of obesity-related type 2 diabetic patients is gradually improving. The main gastrointestinal bariatric surgeries performed in clinical settings include Roux-en-Y gastric bypass (RYGB), laparoscopic adjustable gastric banding (LAGB), laparoscopic sleeve gastrectomy (LSG), and biliopancreatic Diversion-Duodenal switch (BPD/ DS), etc. Among them, gastric bypass surgery (RYGB) and laparoscopic gastric banding (LAGB) are the most common. 1. Gastric bypass surgery (RYGB): As early as the 1950s era Edward Mason reported reversal of disease in type 2 diabetic patients after gastric bypass surgery. Gastric bypass surgery began in only a few obese type 2 diabetic patients, but was associated with more serious complications such as infection, gallstones and hernias. As the technique continues to improve, RYGB is now the most commonly used procedure. Of the 180,000-200,000 surgical obesity treatments performed in 2006, 80% were performed with RYGB. RYGB can achieve satisfactory long-term weight loss, mitigate 95% of complications in patients with type 2 diabetes, and achieve clinical remission in 80% of diabetic conditions. Both early and late complications are low, and surgical mortality rates range from 0.2 to 1%. In addition to significant weight loss, RYGB can reverse and reduce major cardiovascular as well as metabolic risk factors, including type 2 diabetes and abnormal lipid metabolism, reduce long-term morbidity and mortality associated with obesity, and reduce health care costs. Approximately 20% of people after this procedure fail to maintain their weight, resulting in weight loss failure. Bypass is currently recommended in the NIH guidelines only for people with a BMI greater than 40. At the 2008 EASD meeting in Rome, 78% of attendees supported lowering the standard of surgical treatment to a BMI of 30 to benefit the more than one million diabetes-related deaths each year. 2. Laparoscopic gastric banding (LAGB) Since LAGB was first reported in 1992, it has been widely performed worldwide and was approved by the US FDA in 2001. LAGB does not destroy the normal anatomical structure of the stomach, and has the advantages of fewer operation steps, less surgical risks, fewer and milder postoperative complications, complete restoration of the gastric body after removal of LAGB, and lasting and obvious weight loss effect. The procedure involves binding the upper end of the stomach with an adjustable band to form a small 15 ml sac. This band can be adjusted to become enlarged or reduced in size to help the patient continue to lose weight until the desired goal is reached. Clinical remission has been achieved in 30-70% of patients with type 2 diabetes via LAGB. In Asia, LAGB has been tried in some provinces and cities in China, in addition to Japan. Diabetic patients with BMI ≥ 35 kg/m2 have been formally listed as having indications for surgery in the guidelines for the prevention and treatment of diabetes developed by the American Diabetes Association Annual Scientific Meeting in 2009. The internationally recognized indications for surgery are: (1) International Health Organization (WHO) criteria: BMI ≥ 40kg/ m2 or BMI ≥ 35kg/ m2 and the presence of obesity associated diseases; (2) Asia-Pacific criteria: BMI > 37kg/ m2 or BMI > 32kg/ m2 and the presence of diabetes or more than 2 other associated diseases. In China, guidelines for the surgical treatment of obesity have also been established (2007): concomitant diseases caused by simple excess fat (metabolic disorder syndrome) are the indications for surgery in selected patients. Specifically, (1) the presence of a metabolic disorder syndrome associated with a simple excess of fat is confirmed and weight loss is predicted to be effective; and (2) stable or steadily increasing weight with a BMI ≥32 for more than 5 consecutive years is determined by a physician to be a comprehensive indication for surgery. At the 2009 Annual Meeting of the European Association of Diabetes (EASD), an investigator reported that surgery on non-obese diabetic animals can control their diabetic condition, and in terms of short-term and medium-term efficacy, it can also improve the diabetic condition in non-obese diabetic patients, and HbA1c can be reduced by about 2.5% after surgery, and more than 80% of patients can achieve blood glucose without the use of drugs Satisfactory control was achieved in more than 80% of patients without medication. The investigators therefore suggest that gastrointestinal bariatric surgery should also be the treatment of choice for diabetic patients who are mildly or moderately obese and overweight. The mechanism of gastrointestinal bariatric surgery for patients with type 2 diabetes is complex. The obvious reason is that after gastrointestinal surgery, their gastric contents or food are changed during the process of passing through the gastrointestinal tract, resulting in a reduced intake of food or a reduced ability to absorb it, as a way to reduce caloric intake and lose weight. However, for diabetic patients, the diabetic condition is significantly improved after gastrointestinal bariatric surgery before significant weight loss has occurred. As research on the pathogenesis of obesity and type 2 diabetes continues to intensify, the important role of the gastrointestinal tract as an endocrine organ and its secretion of some gastrointestinal hormones in the process of food intake and energy metabolism has received increasing attention. Studies have shown that weight loss surgery, while achieving weight loss, alters the secretion and action of gastrointestinal hormones, reduces inflammation and excessive oxidative stress in the obese organism, reduces insulin resistance and improves endothelial function. In addition, some other hormones that regulate energy metabolism, such as leptin, lipocalin and resistin, also play a corresponding role. Coronary heart disease and hypertension are the important causes of death in morbid obesity, with a mortality rate of 19.3/10,000, while tumor and diabetes are the other two important causes of death in obesity, with mortality rates of 15/10,000 and 3.5/10,000, respectively. /Bariatric surgery can also increase the survival rate of patients with a BMI above 45. Gastrointestinal bariatric surgery can effectively reduce weight and significantly improve diabetes in a short period of time. However, there is a lack of sufficient evidence on the long-term effects and therapeutic efficacy of surgery. The results of the Swedish Obesity Study (OSO), which followed patients who underwent gastrointestinal surgery for 15 years, showed that maintenance weight loss of more than 10% was achieved in both men and women, regardless of whether binding, bypass or anastomosis was performed. The incidence of new-onset diabetes was reduced by up to 75% compared to controls at 10 years of follow-up, and clinical remission of diabetes was still achieved at 36%. There is a lack of large scale evaluation of the long-term efficacy and safety of gastrointestinal bariatric surgery for the treatment of morbid obesity and related diseases in the Asian population. Gastrointestinal bariatric surgery has been initiated in some cities in China, but it is basically in the initial stage. The joint endocrinology and surgery departments of our hospital have already carried out surgical treatment for morbid obesity, while long-term observation of patients’ endocrine metabolic status and guidance on post-operative lifestyle are carried out.