Insulin injection is subcutaneous injection, not intradermal injection. At present, insulin injection is basically subcutaneous injection, and the main injection site is the abdomen, and it should not be injected into the muscle layer, or even deeper, otherwise it can affect the absorption rate of insulin, leading to the slow onset of the drug, large fluctuations in blood glucose and other adverse reactions. The dosage form of insulin should be confirmed before use. If insulin injection pens are used, the needles should be installed first, and then the injection site should be sterilized; if premixed insulin is used, the drug should be mixed first and the appropriate dosage should be adjusted. Patients should follow the doctor’s instructions to use insulin and avoid blindly using the drug on their own, so as not to use it wrongly and affect the efficacy of the drug.