Diabetes is a chronic disease with glucose metabolism disorder. Long term hyperglycemia leads to chronic damage of the kidneys, heart, blood vessels, nerves, and other organs. Sodium/ glucose cotransporter 2 (SGLT2) inhibitors are a new type of hypoglycemic drug that reduces the blood glucose level by a new mechanism independent of insulin secretion. Such drugs reduce the renal glucose threshold by inhibiting SGLT2, which is responsible for reabsorption of glucose in urine in the renal tubules of the kidney, and expelling excess glucose, thereby reducing the glucose level in blood circulation. Additionally, SGLT2 inhibitors not only treat diabetes, but can also be used to treat cardiovascular, renal, hypertension, and other diseases caused by diabetes. This article reviews the role and mechanism of SGLT2 inhibitors in diabetes and its complications.