The Pro/E software was used to generate 3-D model of pneumatic hammer housing casting. The solidification process of the casting was simulated by the numerical simulation software, View Cast. The location and scale of the shrinkage defects were shown in the results. The risers were designed by the View Cast software based on the simulation results. The reasonable risers were obtained after the optimization on the numerical simulation. And the parameters of gating system were got according to the simulation results calculated by the gating system designing function of View Cast. Then the solidification results demonstrated that the risers and pouring system could be planned by View Cast effectually. The reasonable casting process was obtained and the process has been proofed by the productive practice.