Objective:To explore the method and effect of free thining anterolateral thigh perforator flap (ALTP) in repairing soft tissue defect of scar contracture deformity after hand trauma.Methods:From March, 2015 to August, 2019, 12 patients who suffered scar contracture after hand trauma were repaired with thin ALTP. First, completely resected the scar contracture tissue from the hands and restored the normal bone structure and force line of the hand. The area of hand wound defects were 5.0 cm×6.0 cm-8.0 cm×10.0 cm. The wound was repaired by free ALTP, and the flap was micro-thinned for the first time. The flaps did not carry broad fascia, and the donor sites were directly sutured. The wound healing, the flap appearance, texture, sensation, scarring of the donor area, and functional recovery of the affected hand were observed regularly after surgery. The patients were followed-up by outpatient review and WeChat.Results:All the flaps survived well after the operation. Two cases suffered crisis because hematoma entraps vein cause by bleeding from perforator branch. After surgical exploration, the flaps survived successfully. All 12 flaps were followed-up successfully, including 6 cases reviewed in outpatient clinic, 4 cases followed by WeChat video and 2 cases by telephone consultation. The follow-up time was 3-20 months, with an average of 11 months. The flaps were not bloated, soft, non-pigmented, and beautiful in appearance. Only linear scars remained in the donor sites. The gripp function, palm function, thumb opposition function and finger function of the affected hand were largely restored. According to the TAM method of Upper Limb Function Evaluation of the Chinese Medical Association: 7 cases were excellent, 4 cases were good, and 1 case was fair.Conclusion:The thinning ALTP can be used to repair the scar contracture deformity after hand trauma. It can carry different tissues for 3-dimensional repair. After operation, the flap has a beautiful appearance, the donor site can be closed directly, and the damage of donor site can be reduced. It is an effective method to repair the hand contracture deformity.