We sought to assess the early clinical outcome of 3D-multimodality image (3DMMI)based virtual surgical planning for resection and reconstruction of malignant giant pelvic tumors. Patients and methods: In this retrospective case-control study, surgery was planned and performed with 3DMMI-based patient-specific instruments (PSI) in 13 patients with giant pelvic malignancy and without 3DMMI-based PSI in the other 13 patients. In the 3DMMI group, 3DMMI was utilized, taking advantages of computed tomography (CT), contrast-enhanced CT angiography (CTA), contrast-enhanced magnetic resonance imaging (MRI), contrast-enhanced magnetic resonance neurography (MRN), which could reveal the whole tumor and all adjacent vital structures. Based on these 3DMMI, virtual surgical planning was conducted and the corresponding PSI was then designed. The median follow-up was 8 (3-24) months. The median age at operation was 37.5 (17-64) years. The mean tumor size in maximum diameter was 13.3 cm. Surgical margins, intraoperative and postoperative complications, duration of surgery, and intra-operative blood loss were analyzed. Results: In the non-3DMMI group, the margins were wide in six patients (6/13), marginal in four (4/13), wide-contaminated in two (2/13), and intralesional in one (1/13). In the 3DMMI group, the margins were wide in 10 patients (10/13), marginal in three (3/13), and there were no wide-contaminated or intralesional margins. The 3DMMI group achieved shorter duration of surgery (P=0.354) and lower intraoperative blood loss (P=0.044) than the non-3DMMI group. Conclusion: The 3DMMI-based technique is advantageous to obtain negative surgical margin and decrease surgical complications related to critical structures injury for malignant giant pelvic tumor.