Abstract: [Objective] Using surgery combined with chemotherapy to treat patients with primary undifferentiated pleomorphic sarcoma of the femur, to observe the short-term clinical efficacy of patients after limb salvage treatment. [Methods] The clinical data of 10 patients with undifferentiated pleomorphic sarcoma of the femur of the lower extremity diagnosed pathologically from October 2015 to October 2019 in our department were retrospectively analyzed. There were 3 males and 7 females. The age of onset was 16-73 years old, with an average of (47.12±14.91) years old. All patients underwent X-rays, CT and MRI examinations of the primary site, CT scans of the lungs and whole body bone scans, and 10 needle biopsies. Enneking surgical staging: 1 case in stage IIA, 9 cases in stage IIB (including 3 cases of pathological fractures). 4 patients received neoadjuvant chemotherapy (lobaplatin + adriamycin + ifosfamide) before surgery, and 8 patients received chemotherapy (lobaplatin + adriamycin + ifosfamide) after surgery. 1 case received tumor hip reconstruction, 1 case received segmental prosthesis reconstruction, and 8 cases received tumor knee joint reconstruction. According to the International Bone and Soft Tissue Tumor Society (MSTS) scoring system, the postoperative function was evaluated. [Results] All 10 patients in this group were followed up for 7-43 months, with an average of (25.10±11.25) months. 4 cases died, all of them were stage IIB 4 cases (2 cases of pathological fractures), 1 case survived with tumor, and 5 cases survived without tumor. Five cases had lung metastasis or multiple metastases in other parts after operation, the average time of tumor metastasis was (4.40±1.14) months, and 2 cases had local recurrence. The average MSTS score of lower extremities (26.5±1.58) at 3 months after surgery: 1 patient received tumor hip reconstruction, 28 points; 1 patient received segmental prosthesis reconstruction, 29 points; 8 patients received tumor knee reconstruction on average (26.0±1.31) points. [Conclusion] Limb salvage treatment is the main method for undifferentiated pleomorphic sarcoma of the femur of the lower extremity. Wide-range surgical resection and chemotherapy can achieve local disease control and long-term survival, and the possibility of postoperative recurrence and metastasis in patients with pathological fractures and chemotherapy insensitivity Larger. The limb salvage treatment has recovered satisfactory lower limb function.