Unstable blood sugar after gastric cancer surgery can be treated by changing diet structure and using hypoglycemic drugs. As stomach cancer patients need to remove part of their stomach during surgery, the digestive function of patients may be affected to a certain extent after surgery, resulting in unstable blood sugar. Patients can change their diet structure after surgery by consuming liquid or semi-liquid food, such as some rice porridge, soft noodles, etc. Vegetables or meat can be chopped up and put into porridge to be consumed together, in order to reduce the burden of stomach and intestines, eat fewer and more frequent meals, and take appropriate activities to control blood sugar. If the patient’s blood sugar is relatively high, he can take metformin, insulin and other hypoglycemic drugs for treatment to control the blood sugar within a reasonable range. Patients are advised to control their blood sugar under the guidance of a doctor, and not to use medication blindly on their own, so as not to cause discomfort.