Abstract: Objective To analysis of the effect of composite dorsalis pedis free skin flap to repair pollex of large area skin wounds.Methods 12 patients with extensive skin lesions of the thumb and skin were selected.The anterior tibial artery or the dorsal arteries and veins were designed as the pedicle.Leaf flaps，which repair large areas of the thumb with a single defect.Observe the survival of the flap and the healing of the wound.Results 11 cases（91.67%）of the flap survived in the first stage，1 case（8.33%）showed vascular crisis necrosis，and the second stage of skin graft repair after dressing change；11 cases（91.67%）of the wound healed in the first stage.1 case（8.33%）showed subcutaneous flap hematoma on the second day after operation，which led to necrosis of the skin flap and healed after the second stage of skin grafting.1 case of necrosis of the skin graft in the donor site was healed after dressing change.After 4 to 14 months of followed-up，the skin color of the flap recovered well，and the two-point resolution felt an average of 5 to 8 mm.The function of finger flexion and extension is satisfactory.Conclusion The free flap of the dorsal dorsum flap can repair the large area of the skin defect of the thumb.The survival rate of the flap and the wound healing rate are high.The two flaps share a set of blood vessels，simplify the operation and improve the success rate of the operation.The flexion and sensory function of the thumb can achieve “functional repair”，which is worthy of promotion in the clinic.

Key words: composite dorsal foot skin flap, free grafting, skin defect, functional repair