Objective：To investigate the clinical relationship of type 2 diabetes with maligant tumor. Methods：The dead patients with type2 diabetes were stratified into 2 groups according to whether they suffered from maligant tumor. The number, sex, the course of diabetes, blood pressure and some biochemical results were compared between the two groups, meanwhile the incidence and the sorts of tumor were analysied. Results：The average dead age of the patients with diabetec mellitus was（73.57 ± 10.17） years. The incidence of malignancy among the patients was 28.35%（57／201）. The top three kinds of maligancy were digestant cancer, hematal cancer and lung carcinoma. The systolic blood pressure，HOMA-IR, plasma insulin and triglyceride were increased. Conclusion：Type 2 diabetes mellitus is correlated with malignancy which has special distributing rule.The pathogenesis of cancer is unclear, and insulin resistance may be involved in it.