Objective:　To evaluate the therapeutic effects of retrograde interlocking intramedullary nailing under arthroscopy on supracondylar femoral fractures.rn　　Methods:　From June 1999 to December 2000, 17 patients with supracondylar femoral fracture were treated with arthroscopically assisted implantation of retrograde interlocking intramedullary nail and close reduction.rn　　Results:　More than 6-month follow-up study after operation in 11 patients revealed that the average healing time was 3 months. Average range of the knee motion for all the patients was more than 90 degrees. There was no implant breakage and infection.rn　　Conclusions:　This new method, combining the advantage of arthroscope and retrograde interlocking intramedullary nail, can provide a stable and reliable fixation, and meanwhile is less invasive to the soft tissue and knee, less operative time and blood loss, minimal disruption of the blood supply in fracture site. It is conducive to the fracture healing and the functional recovery of the knee joint and worthwhile to be recommended.