The method of disinfection before surgery is related to the degree of contamination of the disinfected site, and usually disinfects three times. For clean areas, disinfection should start from the center of the surgical field to the surrounding area, which is called centrifugal disinfection, and for the perineum, anus or infected wounds, disinfection should be carried out from the outside to the inside, which is called centripetal disinfection. Povidone-iodine is commonly used for three times disinfection. The operator disinfects the arm after holding the oval forceps standing on the right side of the patient, holding the povidone-iodine cotton ball, the first disinfection from the center of the operation, without omission to the surrounding skin disinfection, when the disinfectant solution is dry, change the sterile oval forceps, in the same way to disinfect the second, and so on, for the third disinfection, each disinfection is not more than the disinfection of the previous disinfection range. It should be noted that the head end of the oval forceps should be kept lower than the grip end all the time during the sterilization process. The disinfection area is 15-20 cm around the surgical incision.