Objective To evaluate biomechanical strength of locking compression plate (LCP) for fixation of periprosthetic proximal femur fractures (PPFF). Methods Eight matched pairs of Vancouver type B1 adult cadaveric PPFF specimens were fixed with the LCP and the inverted distal femoral less invasive stabilization system (LISS), respectively. Four bicortical locking screws (LCP group) and four unicortical locking screws were used to the length of prosthesis stem, and four double cortical locking screws were used to fix the distal end of the fracture in two groups, the distance from the locking screws to the fracture were also equal. The maximum bending load, maximum bending displacement, bending stiffness, maximum torque, maximum torsional angle and torsional stiffness of two groups in four-point bending test and torsion test were compared and analyzed. Results The maximum bending load, maximum bending displacement and bending stiffness of LCP group were all larger than those of LISS group, but the difference was not statistically significant (P>0.05). The maximum torque, maximum torsional angle and torsional stiffness of LCP group were obviously larger than those of LISS group，and there was a statistical difference between two groups (P<0.05). Conclusions The stiffness of anti-torsion with LCP is significantly better than that with LISS. Consequently, LCP has better biomechanical stability for PPFF.