Objective:To explore the surgical technique and clinical effect of pressure boost in repairing soft tissue defects of limbs with thinned anterolateral thigh perforator flap (ALTP) .Methods:From January, 2015 to December, 2018, 18 cases with soft tissue defects of limbs with various damages of blood vessels and nerves with explosure of tendon and bone. There were 13 males and 5 females aged between 18 to 56 (averaged of 36.3) years, which were 6 defects in shank, 4 in foot and ankle, 5 in forearm, and 3 in hand. The soft tissue defect area was 7 cm ×12 cm to 13 cm ×30 cm. Thinned ALTP was used to repair the wound surface. The perforating vessels of the distal flap were anastomosed with one branch of the internal vessel pedicle flap to increase the pressure hence the blood supply of the distal region. The donor sites were sutured directly or covered by skin graft. Followed-up was conducted by 1-2 monthly clinic visits and telephone or on-line review to check the flap survival and recovery of functions.Results:All flaps survived without arterial or venous crisis. One flap had partial necrosis at the distal end, and healed after dressing change. One case had a swelling flap due to a congestion beneath the flap. The wound achieved primary healing after removal of sutures, ligation of subcutaneous vessels and drainage of hematoma. All patients were followed-up for 6 to 18 (average, 9.5) months. All flaps had good appearance and texture. After rehabilitation treatment, most of the joint activity had been recovered: extension and flexion of wrists joints ranged 60°-80°, 70°-80° for metacarpophalangeal joints and 40°-60° for ankle joints. One patient underwent ankle joint dorsiflexion function reconstruction and flap thinning at 6 months after operation due to the defects of most of the extensor tendon.Conclusion:During the use of free ALTP to repair soft tissue defect of limbs, application of the technique of pressure boost is able to increase blood supply to the distal region of flap. It helps to reduce the incidence of infection and necrosis at the edge of the flap.