Abstract: In this study, tibial shaft fracture has been treated with implants as numerically to investigate the stress behavior and the effect of plate material, position and length under pressure load. Plates of stainless steel, titanium alloy(Ti6Al4V), or CF-PEEK(CF50) were used to fix the tibial shaft comminuted fracture in different location and different working length. The maximum stress, the maximum micromotion of fracture and the stress shielding of cortex bone were analyzed. CF50 is more ideal biomechanical fixation material than traditional metal material for the treatment of tibial shaft comminuted fractures. In the treatment of tibial shaft comminuted fracture, lateral position and with relatively long working length of the plate have the advantages in micromotion, stress and stress shielding rate of the fracture end.