Insulin injections are given by subcutaneous injection, and it is best to use a 1 ml syringe each time to ensure accurate dosing. Subcutaneous tissues without human vascular nerves should be chosen to avoid injecting into the muscle layer. The medication should be drawn in the order of short-acting, then medium- and long-acting insulin, mixed and then injected. Insulin injection usually selects the abdomen, the lateral 1/3 of the upper arm, the upper 1/3 of the lateral thighs bilaterally and the lateral upper hip bilaterally. The location must be changed each time, and do not inject twice in the same area within a month to avoid local subcutaneous fat atrophy and hardening. In addition, since exercise can accelerate the absorption of insulin, the exercise area should be avoided when injecting. From the abdomen, upper arm, thigh to hip, the absorption of insulin injection site is from fast to slow. Different types of insulin have different absorption speed at the injection site because of different efficacy, so patients need to inject under the guidance of doctors according to their own condition. For ultra-short-acting insulin analogues, the absorption rate is not affected by the injection site and can be injected at any site. Short-acting insulins should be injected abdominally for the fastest absorption of insulin. Medium- and long-acting insulin and long-acting insulin analogues are recommended to choose thigh or buttock injection, which can make the insulin absorbed slowly. Premixed human insulin and premixed insulin analogues are recommended to be injected before breakfast, in the abdomen, which can speed up insulin absorption and lower blood sugar after breakfast, and injected in the thigh or hip before dinner, which can delay insulin absorption and prevent nighttime hypoglycemia.