Objective: To explore the effects of using free transplantation of expanded perforator flaps in the treatment of severe scar contracture deformities in children. Methods: From January 2010 to December 2018, 18 pediatric patients with severe scar contracture were admitted to Xijing Hospital of Air Force Medical University, and 3 pediatric patients with severe scar contracture were admitted to Shenzhen Hospital, Southern Medical University. There were 14 males and 7 females among the 21 pediatric patients, who were 3-12 years old, with 15 cases of cervicothoracic adhesion, 5 cases of chin-chest adhesion, and 1 case of ankle joint contracture. According to the location of scar contracture and the size of wound after release, the donor site of perforator flap and expander volume were selected, and the expander was inserted to expand the flap. After expanding to proper volume, the contracted scar was resected and released. The perforator flap was designed and transplanted freely according to the wound. The flap area ranged from 14 cm×6 cm to 18 cm×15 cm. The location of the expanded flaps, the number, location, rated volume, and the location of injection port of the inserted expanders, the survival condition of flaps, the complications, the repair of donor sites, and the follow-ups were analyzed. Results: Among this group of pediatric patients, 16 cases used expanded thoracodorsal artery perforator flap, 3 cases used expanded circumflex scapular artery perforator flap, and 2 cases used expanded anterolateral thigh perforator flap, with 14 cases of pure donor site expansion and 7 cases of donor site expansion together with expansion beside donor site. Thirty-four expanders were inserted in 21 pediatric patients, with 21 under flaps, 6 near scars, and 7 near donor sites. The rated volumes of 26 expanders were 200 mL, while those of the remaining 8 expanders were 400 mL. Eight injection ports were placed externally, while the rest were placed internally. All the 21 flaps survived completely. Vascular crisis occurred in 1 pediatric patient 5 days after operation, and exploratory operation and reanastomosis were performed. The donor sites of 19 pediatric patients were closed directly, while the small wounds in lateral thoracic donor sites of 2 pediatric patients were repaired with thin intermediate split-thickness skin graft collected beside the donor site. Follow-up for 6 to 36 months showed that the texture and color of area repaired by the flaps were close to the surrounding skin. The flaps in the neck region of 8 pediatric patients were slightly bulky, requiring debulking operation, while the other cases had good appearance. The movement function of the involved regions was basically restored to normal, and no recurrence of contracture occurred. Conclusions Free transplantation of expanded perforator flaps can achieve favorable appearance, texture, and function restore in treating severe scar contracture deformities in children, and the curative effect is stable and lasts long.