:Objective To investigate the biomechanical characteristics of the modified memory alloy internal fixator for separation of Pubic Symphysis.Method A model of Pubic Symphysis separation injury was established in 10 pelvic specimens,in which the control group was fixed with dynamic compression plate after reduction, the observation group, the modified memory alloy internal fixator for separation of Pubic Symphysis was used after reduction.The biomechanical stability of two kinds of internal fixation was compared.Results There was no loosening and fracture of internal fixation in both groups.The horizontal,anteroposterior,up and down displacement of Pubic Symphysis in the observation group were obviously reduced compared with the control group(P＜0.05).Conclusions The tensile force of the modified memory alloy internal fixator for separation of Pubic Symphysis against horizontal and anteroposterior direction are better than that against dynamic compression plate, which resistance to vertical shear force is better than that of dynamic compression plate.