Intramuscular injection is performed by helping the patient to take a suitable position, sterilizing the injection site, injecting the medicine into the muscle through the syringe in accordance with the principle of aseptic operation, and finally withdrawing the syringe and pressing to complete the operation. Before the intramuscular injection, it is necessary to explain to the patient and check the relevant information of the patient, select the appropriate site, and then fully sterilize. In addition, when injecting two drugs at the same time, we need to pay attention to the contraindications of the drugs to avoid accidents. In clinical practice, the treatment sites include gluteus maximus, deltoid muscle of the upper arm, lateral femoral muscle, gluteus minimus, gluteus medius and other muscle groups that are far away from large blood vessels and nerve routes. Due to the nature of the drug, individual differences, operating skill and other differences, intramuscular injection may appear hardness, redness, swelling, urticaria, bruising and other adverse reactions. When patients experience adverse reactions during intramuscular injection, they need to stop the injection and seek prompt medical attention.