Fat liquefaction, i.e., mechanized necrosis of fat within the wound, is often one of the main causes of poor wound healing after surgery. Fat liquefaction is related to the patient’s body type and intraoperative operation. If the patient is obese, the use of high-frequency electric knife may cause superficial burns of subcutaneous adipose tissue, or part of the adipocytes are denatured due to thermal injury. At this time, the blood supply in the adipose tissue is impaired due to thermal coagulation, resulting in aseptic necrosis of the adipose tissue. In addition, if the incision is exposed for too long and there is irritation such as extrusion, it may also cause aseptic inflammatory reaction and liquefaction of adipose tissue. Trauma, fat grafting, and infection are also common causes of fat liquefaction in the body. When fat liquefaction occurs, it is important to consult a doctor in time to identify the cause of the condition and then follow the doctor’s instructions to treat it.