On October 8th, 2020, a patient with left forearm crush injury was treated. The left forearm was caught in a mechanical belt when he was doing farm work, and was rescued after half an hour of squeezing and rubbing. There were skin, subcutaneous tissue and vascular nerve tendon necrosis on the palm and dorsal side of the left forearm, and there was no blood supply in his hand. In the first stage, the left anterolateral thigh Flow-through perforator flap was used to repair the palm defect of forearm, and the ulnar artery and vein were bridged by the vascular pedicle of the descending branch of the lateral circumflex femoral artery to rebuild the blood supply of limbs. After the condition was stable, the right anterolateral thigh Flow-through perforator flap was taken to repair the dorsal forearm defect and bridge the radial artery and vein. After the operation, the flap survived smoothly with necrotic tissue oozing from the incision and recovered after dressing change. After 3 months and half a year""s follow-up, the flap transplantation site recovered satisfactorily, and the passive motion of wrist joint and hand joint was satisfactory, which laid a good foundation for the second-stage functional reconstruction operation.