Objective To investigate the effectiveness on the re-fracture of the femur with occult infection by using non-contact locking plate which was placed under the deep fascia. Methods Clinical data of 12 cases of occult infective re-fracture after femoral fracture operation were retrospectively analysed between January 2010 and December 2014. There were 8 males and 4 females with an age of 28-69 years (mean, 42.8 years). Femur re-fractured in 5 cases after 3 days to 4 weeks (mean, 10.6 days) of removal of internal fixation, including 4 cases of plate fixation and 1 case of intramedullary nail fixation; femur in 7 cases re-fractured because of breakage of internal fixator after 7-16 months (mean, 9.3 months) of internal fixation, including 5 cases of plate fixation and 2 cases of intramedullary nail fixation. The tissues near the fracture were collected for bacteria culturing and pathological examining. All the patients were treated by debriding the site of the fracture, bridging with the non-contact locking plate, and transplanting with granulated cancellous bone autograft. Intravenous infusion of antibiotics were used for 2-3 weeks after operation and oral administration for 4 weeks. The X-ray films were taken regularly and the function of the knees were evaluated by the Hospital for Special Surgery (HSS) score system. Results The results of bacteria culturing were positive in 8 patients and negative in 4 patients, and the pathological results of all the patients were confirmed to be chronic bone infection. All the fractures healed with no signs of exudation and ulceration of the incisions. The 12 patients were followed up 18-36 months (mean, 29.6 months). The fracture healed well and no re-fracture occurred. The fracture healing time was 14-22 weeks (mean, 18 weeks). At last follow-up, the function of the knee joint was excellent in 9 cases and good in 3 cases according to HSS score system. Conclusion The treatment of re-fractures after femur fracture operation needs to determine whether there is an occult infection, and non-contact locking plate placed under the deep fascia is an effective way for the re-fracture.