Objective By comparing biomechanical properties of two-screw rod and three-screw rod for fixing pelvic fracture, the difference in mechanical effects of different screw rod fixation positions in pelvic minimally invasive surgery was studied.Methods The mechanical models of pelvis fixed by two-screw rod and three-screw rod were established, and biomechanical characteristics of the pelvis during standing on both legs, during single-legged standing on healthy side or affected side, as well as in sitting posture were compared and analyzed by finite element simulation, and the fixation effect of three-screw rod was verified by clinical experiments.Results Both fixation methods could restore mechanical transmission of the pelvis. But for three-screw rod fixation, the stress on both sides of the pelvis was more balanced, and the displacement of the whole body and fracture surface was also lower during single-legged standing.Conclusions The three-screw rod fixation has an excellent effect in stability, which is more beneficial for fracture recovery.