Selenium deficiency is an important factor for diabetes. Adequate intake of selenium can ensure the normal function of the pancreas and prevent the destruction of pancreatic β cells. Selenium has a similar effect to insulin, which can protect and restore pancreatic function, improve the metabolic regulation of diabetes, and reduce the level of glycosylated hemoglobin in the urine. Especially for the complications of diabetes (cataracts, lower extremity edema, cardiovascular disease, etc.) has a good control effect.