[Summary] During recent years, increasing evidences have indicated that type 2 diabetes mellitus(T2DM) might increase the risk of certain tumors; the process might be not only related with the chronic pathologic status of T2DM such as hyperglycemia, hyperinsulinemia, insulin resistance, dyslipidemia, status of chronic inflammation but also associated with the long-term use of anti-diabetic drugs (i. e. sulfonylureas, biguanides, glitazones, dipeptidyl peptidase-4 inhibitors, glucagon-like peptitide-1 receptor agonists), as well as the use of insulin and insulin analogues. Herewith a system review was made about the recent progress in studying T2DM and tumor risk.