Arbitrary flap formation is a common method of repairing skin defects, mainly used for skin defects and difficult to close wound sites. Arbitrary flap formation involves cutting a piece of skin tissue with a tip that has not been severed at the root at the site next to the surgical wound and transferring it to cover the wound. Typically, a certain aspect ratio is preserved to allow the skin tissue to receive an adequate blood supply to prevent the flap from moving and causing it to become necrotic. Once the flap tissue and the base of the wound have grown into one piece, blood from the traumatic wound can be supplied to the flap tissue to repair the broken skin. At present, there are also improved ways of arbitrary flap, such as paying attention to the axialization of arbitrary flap, i.e., when removing the flap, the part that is not cut off needs to be left with blood vessels to supply blood, the length and width of the flap can be adjusted, and the appropriate length and width ratio can be more flexible to repair the traumatic wound of broken skin. Any flap formation surgery, pay attention to the anastomosis of the anastomosis, to prevent the flap free to make it necrosis, to ensure good wound healing, to avoid vasospasm, thrombosis and other disorders.