Abstract: The value of surgery in the diabetes mellitus treatment receives much attention in the medical field, however, Chinese metabolic surgeons adopt the surgical experience from surgeries for morbid obesity in western countries. There are many controversies on the operative indication, operation method and postoperative followup of surgery for diabetes mellitus with low body mass index (BMI). Our nation has a large number of patients with diabetes mellitus and low BMI, in which unchecked operative indication, unstandard operation method and nonsystematic followup are common problems. It has profound significance to investigate operative indication, operation method and efficacy evaluation for patients with diabetes mellitus and low BMI.