Objective:To investigate the effect of internal fixation of medial support and lateral wall on initial weight-bearing stability of femoral intertrochanteric fracture after reconstruction of intertrochanteric fracture.Methods:Based on the digital model of Sawbones femur, intertrochanteric fracture models with different medial support and lateral wall states were constructed. Combined with various intramedullary and extramedullary fixation methods, the mechanical models after fixation were simplified, and seven mechanical simplified models were obtained. The individual body weight load (70 kg) was simulated by applying concentrated force (700 N) to the end nodes of the femoral head. Through the analysis and calculation of each model in StrucMaster software, the axial force, shear force, bending moment, displacement deformation, and support reaction force of each bar in each mechanical model were obtained, and the results were output through the supporting SMConsole.Results:The median bending moment of model 1 was 11.55(5.57, 18.00) N·m, and the median bending moment was 2.89(2.81, 2.94) rad. The median bending moment of model 2 was 13.72(9.30, 20.05) N·m, and the median bending moment was 2.93(2.77, 3.05) rad. The median bending moment of model 3 was 19.65(10.23, 26.11) N·m, and the median bending moment was 2.93 (2.77, 3.05) rad. The median bending moment of model 4 was 25.95(25.14, 36.70) N·m, and the median bending moment was 4.38(3.16, 5.15) rad. The median bending moment of model 5 was 13.66(7.99, 25.62) N·m, and the median bending moment was 3.50(3.32, 3.56) rad. The median bending moment of model 6 was 24.60(9.33, 29.37) N·m, and the median bending moment was 3.90(3.69, 4.10) rad. The median bending moment of model 7 was 41.14(0.16, 41.30) N·m, and the median bending moment was 5.50(5.50, 7.05) rad. The mechanical properties of model 1 were better than those of the other six models.Conclusion:The simplified mechanical model and its mechanical calculation analysis based on the lever reconstruction balance theory can be used to preliminarily reveal the mechanical characteristics of femoral intertrochanteric fractures after internal fixation. The internal fixation methods of the medial support and lateral wall of femoral intertrochanteric fracture reconstruction can improve the initial stability of the weight bearing after internal fixation of femoral intertrochanteric fractures and have guiding significance for the functional rehabilitation of early postoperative weight bearing.