[Objective] To investigate the clinical efficacy of induced membrane technique in the treatment of Cierny-Mader Type IV femoral chronic osteomyelitis. [Methods]From January 2016 to December 2019, we performed two-stage surgery on 42 patients with type IV femoral osteomyelitis. In the first stage, membrane induction technology combined with internal fixation was used after thorough debridement. In the second stage, the average postoperative time was (9.21 ± 1.83) weeks. The perioperative period, follow-up and imaging data were observed。[Results] .After the first-stage operation, the length of the bone defect was 5-16 cm, with an average of (8.24±1.16) cm. There were 28 cases of positive deep tissue culture, including 17 cases of Staphylococcus aureus. The infection recurred after debridement in 6 cases, and healed after re-debridement.After the second stage operation, there were 5 cases of infection at the iliac bone extraction site, of which 3 cases had continuous pain, which was relieved after symptomatic treatment.With the passage of time, hip extension and flexion, range of motion (ROM), Harris hip function score, hospital for Special Surgery knee score (HSS) and Paley method were significantly increased (P < 0.05).At the last follow-up, all patients achieved clinical fracture and defect healing, and the healing time ranged from 6 to 16 months, with an average of (9.42±2.53) months。?[Conclusion] The treatment of Cierny-Mader type IV femoral chronic osteomyelitis with induced membrane technique combined with internal fixation after radical debridement can effectively control the infection, accelerate bone union, and reduce complications. It is beneficial to the recovery of affected limb function.