Abstract: The function of β cells is closely correlated with the onset of type 2 diabetes mellitus. Currently the bariatric surgery has been considered to be the most effective therapy for ameliorating the complications and improving the prognosis of type 2 diabetes mellitus, while the mechanism remains unknown. The improvement of β cells function following bariatric surgery might play important roles in the remission of type 2 diabetes mellitus. In this article, the relationship between the changes of related factors after bariatric surgery and the function of pancreatic β cells is reviewed.