The extent of skin preparation varies according to the site of surgery. The scope of skin preparation for open and laparoscopic surgery is basically the same, focusing on the abdominal wall; the scope of skin preparation for perineal surgery focuses on the perineum. 1. Open surgery: the skin preparation range is up to the root of the breast, down to the pubic symphysis, both sides should be over the mid-axillary line, and include the anterior upper third of the thigh. 2. Laparoscopic surgery: the skin preparation range is up to the root of the breast, down to the pubic symphysis, both sides should be over the mid-axillary line, and include the anterior upper third of the thighs, in addition to the perineal skin preparation. For combined anesthesia or lumbar anesthesia or epidural anesthesia, the anesthesia site on the back should also be prepared. 3. Perineal surgery: the skin preparation starts from 10cm above the pubic symphysis to 5cm below the anus, crosses the mid-axillary line on both sides, and also includes the upper 1/3 of the medial inguinal area on both sides. The purpose of skin preparation is to remove the hair on the surface of the skin around the proposed incision in order to reduce the chance of infection by bacteria and other microorganisms. The doctor should be consulted and should not decide on the extent of skin preparation without authorization.