Abstract: Background　In limb-salvage surgery for bone tumors, the safety of osteotomy margins is directly associated with local recurrence and long-term prognosis. In some cases of distal femoral bone tumors, multiplanar individualized osteotomy is required, and maintaining safe margins under complex anatomical conditions remains clinically challenging.Objective　To evaluate the execution stability and osteotomy accuracy of the TIANJI robotic system in individualized osteotomy of the distal femur and to compare its performance with freehand osteotomy. Methods　Twenty-four left femoral synthetic bone models were used to construct distal femoral lesion models. Sixteen models were assigned to the robotic group, including a two-plane osteotomy group (n=8) and a three-plane osteotomy group (n=8). Eight models were assigned to the freehand group, all undergoing the two-plane osteotomy protocol. In the robotic group, preoperative osteotomy planning was performed based on CT images, and intraoperative registration was completed using cone beam computed tomography (CBCT). Postoperatively, the distance error and angular deviation between the actual and planned osteotomy planes were measured. Results In the robotic group, the mean absolute distance error was 0.64±0.30 mm in the two-plane osteotomy group and 0.67±0.31 mm in the three-plane osteotomy group, while the mean angular deviation was 0.76±0.30°and 0.71±0.36°, respectively, with no statistically significant differences between groups (P =0.783 and 0.645). No obvious tendency toward deviation to the tumor side was observed in either group. The minimum signed distance error in the three-plane osteotomy group was -1.16 mm. Under the two-plane condition, the robotic group showed lower mean absolute distance error and angular deviation than the freehand group (0.64±0.30 mm vs 3.95±0.99 mm, and 0.76±0.30° vs 6.62±1.89°, respectively; both P＜0.001).Conclusion　The TIANJI robotic system demonstrated good execution stability and osteotomy accuracy in multiplanar individualized osteotomy using synthetic bone models, and its osteotomy accuracy was superior to freehand osteotomy under the two-plane condition.