Insulin injection is one of the commonly used methods for clinical control of diabetes mellitus, and the sites for insulin injection in clinic mainly include the abdomen, the outer side of the upper arm, and the outer side of the thigh. 1. Abdominal injection: the abdomen is a common site for insulin injection, mainly injecting short-acting insulin. The absorption of insulin injected into the abdomen is fast and even, and the injection process should try to avoid the site of three fingers around the umbilicus. 2. Upper arm lateral injection: the absorption speed is also faster, but the subcutaneous tissue is thinner, it is easy to be injected into the muscle, it is best to choose a 45-degree angle into the needle. 3. Lateral thigh injection: the absorption speed is slower, can be injected with medium and long acting insulin, not suitable for the thin and weak people, it is easy to inject into the muscle. Try to avoid injecting the same part of the body as often as possible, because it is easy to cause subcutaneous hard knots, affecting the absorption of drugs. If there is obvious redness, swelling and pain after injecting insulin, you need to stop injecting in the corresponding area and go to the hospital in time for medical treatment.