[Objective] To introduce the surgical technique and preliminary clinical results of 3D printed guider assisted pelvic tumor resection and reconstruction. [Methods] From January 2017 to October 2018, 18 patients underwent 3D printed guider assisted pelvic tumor resection and reconstruction in our hospital. Before operation, the margin of abnormal signals on the preoperative images were identified, and the tumor size and extent of tumor invasion were determined. After 1:1 real pelvis model was made by 3D printing, a surgical simulation was conducted to create the resection and reconstruction plan, and design the corresponding guider. In the actual operation, tumor resection and pelvic reconstruction were performed according to the preoperative plan and guided by the 3D printed guider. [Results] All 18 patients had operation completed successfully, and were followed up for 18~24 months. During the follow-up period, all 18 patients were alive without deaths due to the tumors. The Musculoskeletal Tumor Society (MSTS) score significantly increased from (12.6±2.0) preoperatively, to (18.6± 1.2) at discharge, and (21.3±1.1) at the latest follow-up, which was statistically significant (P＜0.05) . Compared with those preoperatively, the bilateral differences between the affected side and healthy side in term of the distance of rotation center to midline, acetabular antever- sion and acetabular abduction angle reduced significantly (P＜0.05) . During the follow-up period, no internal fixation loosening or breaking, and local recurrence were found in anyone of them. [Conclusion] The application of 3D printed acetabular guider in pelvic tumor resection and reconstruction has benefits of shortening operation time, improving postoperative recovery, and prognosis.