Asymmetric wall products are widely used in the engineering. However, there are many limitations in the traditional forming processes employed to produce them. Oil pump stator has been studied as an instance to present the forming process of asymmetric wall products. First, a theoretical analysis of the forging's forming process has been made. Second, a rigid-visco-plastic finite element model of oil pump stator has been constructed and three dimensions FEM simulation and analyzing of extruding process have been taken by employing the simulation software. At last, parameters of the forming process have been optimized, the rule of forging's metal flow in the forming process has been analyzed and some distributions of stress and strain have been offered. These data can be use to direct the production of the other asymmetric wall forgings.