A three-dimensional finite element program, HydroForm-3D, based on a rigid-plastic model for the analysis and design of hydroforming process was developed. Several typical hydroforming processes such as tee extrusion, cross extrusion, the hydroforming process combined with the pre-bent process and rear axle housing are analyzed by using this numerical program. The hydraulic pressure force is added to the normal direction of the tube workpiece by integrating the pressure. The predicted simulation results provide insight and understanding into the actual design. This numerical approach to the hydroforming process will benefit the development and application for a wide range of automobile structural components.