The steps of dressing change for infected wounds are generally as follows: i. Fully inform the purpose of dressing change before the dressing change, and obtain the cooperation and understanding of the patient. Second, the outer layer of the wound dressing is torn off slowly by hand to avoid pain caused by too fast action, and the inner layer dressing can be torn off with sterile forceps. Third, after opening the wound, observe the incision for redness, swelling, fluid accumulation and other manifestations, give vital iodine cotton balls and disinfect the skin around the wound two to three times. Inside the wound, first wipe the secretion with saline cotton ball to fully reveal the wound. IV. Clean the inside of the wound with vital iodine cotton ball, hydrogen peroxide cotton ball and saline cotton ball in turn, and for accompanying obvious necrotic tissue, debridement treatment needs to be given. Fifth, after finishing, local external application of vital iodine cotton ball, or saline cotton ball can be applied to play the purpose of anti-inflammation and swelling, and external application of sterile gauze and dressing, the change of medicine is over.