Objective To investigate the surgical method and effectiveness of repairing traumatic metacarpophalangeal joint defect by the composite tissue flap autograft of the second metatarsophalangeal joint. Methods Between June 2005 and December 2009, 6 cases (6 fingers) of traumatic metacarpophalangeal joint defect were treated with the composite tissue flap autograft of second metatarsophalangeal joint (containing extensor tendon, flexor tendon, proper digital nerve, planta or dorsal flap). All patients were males, aged 18-48 years, including 3 cases of mechanical injury, 2 cases of crush injury, and 1 case of penetrating trauma. The 2nd, 3rd, and 4th metacarpophalangeal joints were involved in defects in 2 cases, repectively, and defects ranged from 1.5 cm × 1.5 cm to 3.0 cm × 2.5 cm in size. All patients had skin and soft tissue defects, and defects ranged from 4 cm × 2 cm to 5 cm × 4 cm in size; and 5 cases complicated by extensor tendon defect (2.5-5.0 cm in length), 3 cases by flexor tendon rupture, and 3 cases by common palmar digital nerve injury. The time from injury to admission was 2-6 hours. Results The composite tissue flaps and skin grafts survived in all cases. All incisions healed by first intention. All patients were followed up 1-5 years. The X-ray films showed good healing between the transplanted metatarsophalangeal joint and metacarpals and phalanges at 9-14 weeks postoperatively. The appearance, colour, and texture of the skin flap were satisfactory, and the senses of pain and touch were recovered. The palmar flexion range of transplanted metacarpophalangeal joints was 50-70°, and the dorsal extension range was 5-10° at last follow-up. According to the functional assessment criteria of upper limb formulated by the Hand Surgery Branch of Chinese Medical Association, the results were excellent in 4 cases, good in 1 case, and fair in 1 case, and the excellent and good rate of 83.3%. No dysfunction of the donor foot was observed. Conclusion The metatarsophalangeal joint composite tissue flap can provide bone, nerve, skin, muscles, and tendons, so it is an effective approach to repair the metacarpophalangeal joint defect and to recover the function of the injured joints in one operation.