Objective To discuss the feasibility and long-term effect of free latissimus dorsi muscle flap in repair of severe lower extremity injury in children. Methods From July 1999 to June 2004, nine child patients (at age of 6-13 years) with severe lower extremity injury involving soft tissue defects a-round the calf and the foot associated with complex open fractures, bare dislocation, and injury of the nerve, tendon and artery were repaired with free latissimus donsi flap, with flap area ranging from 30 cm ×12 cm to 10 cm × 5 cm. Results All the latissimus dorsi flaps survived, with success rate of 100%. A follow-up for 4-9 years showed that the flap had sound shape and function and normal blood supply, without significant influence on donor area. Conclusion Latissimus dorsi flap has advantages of constant anatomical site, abundant blood supply, massive area, strong anti-infection ability and less in-fluence on donor area and hence is an ideal method for repairing severe lower extremity injury in children.