Objective To investigate the biomechanical properties of a novel sacroiliac lag screw with a spiral blade. Methods: Percutaneous sacroiliac lag screws were used as The controls. Polyurethane material was used to simulate the trabecular bone, and the pullout resistance performance was tested on an Instron mechanical testing machine. Subsequently, pelvic specimens were utilized to analyze the static stiffness and dynamic stability of the novel sacroiliac lag screw in repairing sacroiliac joint injuries under normal standing conditions, with normal pelvis, single-sided sacroiliac joint injury pelvis, percutaneous sacroiliac lag screw-single screw repair, and percutaneous sacroiliac lag screw-double screw repair as controls. Results The damage to the polyurethane material after screw extraction was smaller in the novel sacroiliac lag screw group. The average effective holding displacement of the novel sacroiliac lag screw was significantly greater than that of the percutaneous sacroiliac lag screw (P<0.05). However, the maximum resistance to the pullout force for the percutaneous sacroiliac lag screw was significantly higher than that for the novel sacroiliac lag screw (P<0.05). The stiffness after repair of sacroiliac joint injuries was significantly higher when using a single sacroiliac lag screw than when using two percutaneous sacroiliac lag screws (P<0.05). The displacement amplitude was the highest in the sacroiliac joint injury group, followed by that in the normal group. The displacement amplitudes in the other groups were similar; however, the differences were statistically significant (P<0.05). The dynamic stability of the sacroiliac lag screw repair group was the best, slightly better than that of the percutaneous sacroiliac lag screw-double screw repair group, and the dynamic stability of the sacroiliac joint injury group was the worst. The novel sacroiliac lag screw effectively repaired the sacroiliac joint injuries. Conclusions The novel sacroiliac lag screw can effectively hold the trabecular bone and has practical clinical utility.