Objective To identify the postoperative function and short-term outcome of Global Modular Replacement System (GMRS) for reconstruction of defect after removal of tumor so as to supply information for cl inical appl ication. Methods Between March 2007 and May 2009, 30 l imb-salvage cases reconstructed with GMRS were retrospectively reviewed, including 18 males and 12 females with a median age of 25 years (range, 11-57 years). The preoperative diagnoses were osteosarcoma in 15 cases, mal ignant fibro-histiocytoma in 4, giant cell tumor in 3, chondrosarcoma in 2, and Ewing’s sarcoma and angiosarcoma in 1 respectively. The duration of symptom ranged from 1 to 15 months with an average of 5.6 months. There were 4 revision cases at mean time of 3.4 years after index surgeries. The locations were the proximal femur in 3 cases, distal femur in 22 cases, and proximal tibia in 5 cases. According to Enneking stage, 2 cases were rated as stage IB, 1 as stage IIA, and 27 as stage IIB. Four cases were compl icated by pathologic fracture. Results The average operation time was 165 minutes (range, 120-240 minutes); the mean blood loss was 448.3 mL (range, 100-1 500 mL); and the mean resection length was 14.1 cm (range, 7.5-22.5 cm). All the wounds healed by first intention. All 30 patients were followed up 10-35 months (22.3 months on average). Local recurrence occurred in 2 cases (6.7%) at 5 and 14 months respectively and distal metastasis occurred in 5 cases (16.7%) at 4-12 months (7.3 months on average) postoperatively. One patient died of multiple lung metastases at 10 months postoperatively. Twenty-nine patients survived at last follow-up, including 25 cases of tumor-free survival and 4 cases of tumor bearing survival. Aseptic loosening occurred in 2 cases (6.7%) at 1.5 years and 2 years postoperatively respectively. Deep infection occurred in 1 case (3.3%) at 1 year postoperatively. At last follow-up, the Musculoskeletal Tumor Society (MSTS) 93 scores were 4.6% ± 0.7% for pain, 3.7% ± 0.9% for function, 3.2% ± 1.3% for satisfactory degree, 4.3% ± 0.9% for orthesis, 3.7% ± 0.7% for walking, 3.3% ± 1.0% for gait; total score was 75.9% ± 14.2%. The Toronto Extremity Salvage Score (TESS) score was 87.0 ± 7.0. Conclusion Reconstruction for defect after removal of tumor with GMRS has satisfactory short-term outcome with good function recovery and low compl ication rate.