Objective:To explore the methods, complications and follow-up results of limb salvage for primary malignant tumors of the femoral shaft.Methods:From October 2006 to October 2019, 41 cases of primary malignant tumors of femoral shaft were analyzed retrospectively, 37 cases were followed up, including 22 males and 15 females, aged 8-46 years with an average age of 20.56±4.72 years old. All the lesions were located in the femoral shaft, and The Enneking stage was IIB. Tumor lesion ranged in the femur from 10 cm to 24 cm, and there was no pathological fracture. Pre-operative puncture biopsy was performed in all cases.22 cases were confirmed as osteosarcoma, 8 as chondrosarcoma, 5 as Ewing sarcoma, 2 as malignant fibrous histiocytoma. Neoadjuvant chemotherapy has been used to treat both osteosarcoma and Ewing sarcoma. Among the 37 patients, 8 cases of patients received total femoral prosthesis replacement, 14 cases of intramedullary nail fixation with allogenic bone graft, 8 cases of allograft-prosthetic composite (APC), and 7 cases of 3D printed prosthesis. The limb function was graded according to MSTS 93 system.Results:37 out of 41 patients were followed up, and the average follow-up time was 23.15±16.74 months (6-62 months). There were 9 patients with pulmonary metastases (26.47%), among which 6 patients passed away due to multiple metastases. 28 patients survived without tumor at last follow-up. The MSTS score was18-28 (average of 22.55±2.57). The average score of 3D printing prosthesis group was 27±1.74, allogeneic bone transplantation group was 22.85±2.59, total femoral prosthesis replacement group was 20.25±2.25, and the APC prosthesis group was 20.5±2.07. There was statistical difference between 3D printing group and other groups. The overall excellent and good rate of lower limb function was 79.41%, in which the 3D group was 100%, allogeneic bone group was 78.5%, APC prosthesis group was 87.5%, total femoral prosthesis replacement group was 62.5%. There was no statistical difference in the excellent and good rate of limb function among the groups. There weren't any cases of hip joint dislocation after total femoral prosthesis replacement. Delayed union of bone healing was seen in 3 cases of allogeneic bone transplantation and 2 cases APC patients. One patient suffered from the postoperative hemorrhage-related diseases-sciatic nerve compression, and the nerve recovered after emergency debridement. One patient suffered from poor wound healing. The overall complication rate was 24.32% (9/37).Conclusion:The patients with primary malignant tumors of the femoral shaft can effectively recover the lower extremity function by choosing the appropriate surgical scheme, in order to achieve the purpose of limb preservation and improve the quality of life of the patients. 3D printing prosthesis provides a new choice in the treatment of femoral shaft tumors.