The patient should go to the supine position with the upper limb of the affected side abducted at 90° and the back of the affected side padded with a soft pillow to elevate the axilla; 2. The length of the incision is about 15-20cm, which depends on the shape of the patient’s breast. 3.Free flap: After cutting the skin, the flap is free with an electric knife, and the flap is free from the lower edge of the clavicle, the lower edge of the rib arch, the inner edge of the sternum, and the outer edge of the latissimus dorsi muscle. 4.Excision of the whole breast tissue and the pectoralis major muscle fascia, according to the order of upper, lower and inner, the whole breast tissue and the pectoralis major muscle fascia are excised from the pectoralis major muscle surface. 5.Clear the axillary lymph nodes and expose the axilla. The axilla: clear the axillary lymphatic fatty tissue and preserve the important blood vessels and nerves; 6. Treatment of the surgical wound: the surgical wound is usually flushed with distilled water, carefully hemostatic, and after checking that there is no active bleeding on the wound, negative pressure drains are placed to the chest wall and the axilla respectively. The upper and lower flaps or inner and outer flaps are pulled together and sutured, the wound is covered with a dressing for external use, and the chest strap is wrapped with pressure. The negative pressure drainage tube is connected to a negative pressure bottle, and the operation is completed, and the patient is sent back to the ward after waiting for awakening.