Abstract: Bile and pancreatic juice were flowed straight into ileum after Biliopancreatic Diversion surgery，abating. digestive absorption because of that Bile and pancreatic juice transitorily mixed the food.The finding correlates with clinical observations of Biliopancreatic Diversion，which show that the surgeriy may improve effectingly the type 2 diabetes and its complication in a long tine, Having similar effects of gastric bypass surgery,but the mechanism is currently questionable,which may relate with gut hormone, blood fat,the function of islet cell and biliopancreatic diversion.

Key words: Type 2 diabetes, Biliopancreatic Diversion surgery, Gut hormone