The need to shave before surgery generally refers to skin preparation. Usually skin preparation is performed by a nurse. Skin preparation is the surgical preparation of shaving and cleaning of the body surface in the appropriate area for the surgery. It is a normal pre-operative process. The process is highly specialized and needs to be performed by a nurse or a doctor in a hospital. The main purpose of skin preparation is to reduce the number of skin bacteria without compromising the integrity of the skin and to reduce the risk of post-surgical incision infections. Therefore, this procedure generally requires special skin preparation tools and is performed by specialized personnel. It is important to note that the principle of skin preparation is generally based on the fact that the hair in the area interferes with the operation. Therefore, whether, how and when to prepare the skin need to be determined by a professional doctor. It should not be done blindly by yourself, so as not to damage the skin integrity or lose the timeliness of the skin preparation.