The aim of this study was to determine the layout of the personalized plate with high bearing capacity by using topology optimization technology. Taking a typical defected mandible as an example, the finite model of mandible was constructed that considering the properties of bone and scaffold materials. To evaluate the mechanical properties of personalized plate, the stress distribution of mandible, guide and screws were simulated and analyzed under the under same occlusion compared to conventional plate. The results showed that the peak stresses of mandible, plate and screws of personalized plate fixation system were 55.86 MPa, 291.1 MPa and 122.53 MPa, respectively, which were 9.8%, 32.0% and 14.6% lower than those of conventional plate fixation system. Combined with Gibson-Ashby model of face centre cubic structure, the porous structure with elastic modulus equivalent to the cortical bone was designed, and the porosity was 71.6%. The personalized plate designed in this study significantly reduced the peak stress and improves the reliability of the scaffold. Combined with selective laser manufacturing (SLM), personalized prosthesis with excellent structure can be quickly manufactured to meet tight time requirements.