Insulin injection can be chosen from abdomen, lateral upper arm, lateral upper hip, anterior and lateral thigh, etc. Abdominal injection is preferred. The thickness of subcutaneous tissue at the site of insulin injection: upper outer hip＞abdomen＞anterior and lateral thigh or outer upper arm, and the speed of insulin absorption: abdomen＞lateral upper arm＞anterior and lateral thigh＞upper outer hip. In order to fully absorb insulin, the abdomen is preferred for insulin injection, and care should be taken to avoid injecting within 5 centimeters from the umbilicus, followed by the outer side of the upper arm or the anterior and lateral thighs, and lastly the outer and upper buttocks (which is less frequently used). In addition, insulin injection sites need to be rotated regularly and should not be injected in the same place for a long time. Patients with diabetes should inject insulin under medical supervision.