1.Remove necrotic tissue. Necrotic tissue not only hinders wound healing, but also contains a large number of germs on it, which is not conducive to the control of infection. 2.Accurate assessment of the wound. Only when the necrotic tissue is cleaned can the degree of infection of tendons, blood vessels, muscles and bones be judged, which can provide the basis for the subsequent treatment plan. 3.It is beneficial to drainage and drainage of pus. Infection in diabetic patients can spread rapidly along blood vessels and tendons, which makes it easy for this situation to occur: the surface muscles and other tissues look normal, but deeper layers form fistula holes or sinus tracts. Cleaning the wound and opening the wound surface facilitates the drainage of inflammatory tissues and pus from the fistula hole or sinus tract. 4. Provide deep wound tissue for bacterial culture and sensitivity determination. Reasonable use of antibiotics to treat diabetic foot is allowed, but must be based on bacterial culture and sensitivity determination to choose the appropriate antibiotics, must not blindly or abuse antibiotics. 5, facilitate direct contact between the drug and the trauma. A layer of infected necrotic tissue is not conducive to wound healing, after debridement is conducive to drug targeting medication, direct action with the wound surface, the drug effect can be maximized. 6, the chronic wound into an acute wound. In fact, chronic wounds do not heal as fast as acute wounds, and it is possible to convert chronic wounds into acute wounds through debridement.