The main methods of double eyelid surgery are threading and incision. 1. Threading method: It is also divided into multi-point threading and continuous threading. (1) Multi-point threading: Generally, 3 points are chosen, i.e. one point in the center and one point on each side. The upper eyelid skin and subcutaneous tissues are adhered to each other through the buried threads in order to produce double eyelid folds. (2) Continuous Threading Method: The path of threading is longer and usually 1 or 2 layers are buried to create scarring to adhere the eyelid to the subcutaneous tissue. The buried wire method has the advantages of less trauma, faster recovery and shorter operation time, but the effect of the surgery is not permanent, usually 1 to 2 years can be restored to its original form. 2. Incision method: the skin is cut according to the designed blepharoplasty line, the orbicularis oculi muscle is separated and part of the orbicularis oculi muscle and subcutaneous fat tissue are removed, and then the skin at the lower end of the incision is sutured to the upper eyelid levator tendon membrane so that adhesion is produced and the effect of double eyelid is achieved. The incision method is more invasive and has a relatively longer recovery time, but the surgery is more effective and permanent.