This experiment aimed to seek the best design parameters of stiffening rib of injection molding machine′ s front mold plate. In the collaborative environment of Pre/E software and Ansys Workbench software, the Pro/E parameter-relationship module was used to establish the equi-mass model of front mold plate based on the design parameters of the stiffening rib structure size of injection molding machine′s front mold plate. Furthermore, the finite element static analysis module and the parameter design module of Workbench were used to rapidly calculate the corresponding data of mechanical parameters of front mold plate against a series of given values of the structure size of the stiffening rib, which revealed influencing relation of changes in stiffening rib structure on the target variable. Finally, the best design parameter of front mold plate was confirmed within the scope of design variable values by what-if analysis. Through simulation experiments, compared with the original design, the optimized one showed the maximum stress reduced by 10.9% and the maximum deformation decreased accordingly in the simulation test.