Abstract: Objective To investigate the effect of skin soft tissue expansion on repair of large area of scars on extremities. Methods Twenty-five patients with large area of scars on extremities were admitted to our department from June 2007 to October 2014. There were 14 males and 11 females, aged 4 to 36 years. Operations were performed under local infiltration anesthesia or general anesthesia. In the first stage, 1 to 5 cylindrical expanders with capacities of 250 to 600 mL were placed at left or right sides or at upper or lower parts of the scars. In the second stage, scars of 21 patients were repaired with expanded transverse propulsive and lateral flaps, and scars of 4 patients were repaired with expanded perforator flaps whose pedicles were perforators of brachial artery, superior ulnar collateral artery, or posterior interosseous artery according to areas and shapes of the scars. The secondary wound areas ranged from 13 cm×7 cm to 34 cm×18 cm after dissolution or excision of scars. The areas of flaps ranged from 13 cm×7 cm to 20 cm×12 cm. The donor sites were sutured directly. The flaps after operation and follow-up of patients were observed and recorded. Results All expanded flaps survived after operation. And the superficial distal part of flap whose pedicle was perforator of posterior interosseous artery in one patient was with necrosis, and other flaps survived well. During follow-up of 3 to 15 months after operation of the second stage, color and texture of flaps were similar to surrounding skin, while extremities of donor sites were thinner and auxiliary incisional scars formed after expansion. Conclusions Expanded flap is a good way to repair large area of scar on extremities. Bilateral skin of scar is the first choice of donor site of expanded flap. If there isn′t enough skin for expanding on bilateral sides, expanded perforator flap designed at upper or lower part of the scar is another choice to repair the scar.