In recent years, as the quality of life continues to improve, the number of patients with diabetes combined with lung cancer who need surgery is also increasing. Many family members and patients themselves have such concerns as whether surgery with diabetes is not good for wound healing, and high blood sugar causes high sugar content in the incision, so that the incision cannot grow? How to adjust blood sugar for patients with lung cancer combined with diabetes? Today, we will talk about this issue. However, the danger caused by diabetes is far more serious than the problem of incision. Poorly controlled blood sugar will cause disorders of the body’s internal environment, including ketoacidosis and malfunction of water-electrolyte balance, which is a major cause of the wound healing. A series of postoperative complications such as cardiac, hepatic and renal function and increased mortality. In the preoperative period, blood sugar should be controlled and water-electrolyte disorder should be corrected, but don’t lower blood sugar excessively, as experience shows, blood sugar should be controlled at a mildly elevated level, generally 6-14mmol/L, so that neither hypoglycemia nor acidosis will be caused by overdose of hypoglycemic drugs. It is very dangerous to pursue low blood sugar control.