Objective To assess the efficacy of the extra long scapular-lateral thoracic-il ioinguinal siamese flap to repair the contracture deformity of perineal scar caused by burn and to discuss its characteristics. Methods From January2008 to August 2009, 9 patients with contracture deformity of perineal scar after deep II degree to III degree burn were treated. There were 7 males and 2 females aged from 22 to 54 years (35.4 years on average). The course of disease ranged from 8 months to 5 years. All cases had central type of perineal scar. Among the cases, 3 cases were compl icated by abdominal scar, 4 cases by legs scar, and 2 cases by abdominal and legs scar. Scar ulcer was observed in 2 cases. The opening-closing angle of bilateral lower extremities was (29.4 ± 8.8)°. And anus could not expose entirely so that squatting and rel ieving the bowels were difficult in 6 cases. Defect areas after scar resection ranged from 20 cm × 6 cm to 28 cm × 8 cm. The size of extra long scapular-lateral thoracic-il ioinguinal siamese flap ranged from 35 cm × 12 cm to 58 cm × 15 cm. The donor sites were sutured directly. Results Bl ister and necrosis occurred in 1 case and was cured after dressing changed, and others flaps survived with wounds primary heal ing. Incision at donor site healed by first intention. All cases were followed up 6-12 months. The perineal function improved and the partial deformities were corrected. The opening-closing angle of bilateral lower extremities increased to (75.6 ± 11.3)°, showing significant difference between pre- and post-operation (P lt; 0.05). The functions of squatting and rel ieving the bowels recovered well. The perineal scar adhesion recurred in 2 cases after 6 months of operation and were cured after scar resectionand expanding flaps transposition. Conclusion In view of large donating region, great facil ity for transposition, stableand sufficient blood supply, reutil ization as expanded flap, it was an effective treatment and a beneficial trial by applying the transposition of the extra long scapular-lateral thoracic-il ioinguinal siamese flap for contracture deformity of perineal scar caused by burn.