OBJECTIVE To investigate the effect and the significance of soft tissue repairing and functional reconstruction in limb salvage operation on extremity malignant bone tumors by individualized prosthesis replacement after malignant tumor resection with the help of Neo-adjuvant chemo-therapy. METHODS A total of 78 patients with malignant bone tumor were recruited, including 42 males and 36 females. Aged 19~61, with an average of (29.12+/-9.47).Tumor in 14 patients was in the proximal humerus, 11 in the proximal femur, 27 in the distal femur, 3 in femoral middle part, and 23 in the proximal tibial. There were 29 cases of osteogenic sarcoma, 18 chondroma sarcomatosum, 7 malignant enchondroma with pathological fracture, 20 malignant giant cell tumor,and 4 malignant inflammatory myofibroblastoma of the bone. Soft tissue repairing and functional reconstruction were carried out together with individualized prosthesis replacement. The type of the prostheses was as follows: 14 patients had long stem humerus head prosthesis, 50 made hinged knee prostheses with femoral or tibial component, 3 whole femur replacements, 7 long stem femoral head prostheses, 4 long stem hip prostheses. RESULTS All patients were followed up for an average of (26.80+/-8.06) months (4~37 months) and postoperative functions were estimated according to Enneking system. Among the 78 patients, results in 48 (61.5%) were excellent, 17 (21.8%) were good, 10 (12.8%) were fair, and 3(4.9%) were poor. The satisfactory rate was 83.3%. CONCLUSIONS Soft tissue repairing and functional reconstruction in limb salvage operation on extremity bone malignant tumors by individualized prosthesis replacement not only spare the limbs, but also keep their function.It can remove the psychologic obstacles caused by extremity absence, and is effective for bone malignant tumor.