The influence of glucagon on diabetes mellitus has arised widespread attention within the medical researchers in recent years. Diabetes results from 2 reasons: the reduced insulin by β cells or the over-secreted glucagon by α cells. The secretion of glucagon in Type 2 diabetes patients is more than that in the healthy people. According to a number of clinical trials, the level of glucagon in patients suffered from Type 2 diabetes mellitus has decreased after they take either oral hypoglycemic agents or insulin, suggesting that glucagon is closely related to the occurrence and development of Type 2 diabetes mellitus.