For many key process parameters in such a hydroforming hole piercing operation, the fluid pressure and the piercing force might be the most important process parameters that determine a quality of hydroformed parts. However, designing such process parameters is still arrived at based on extensive trial-and-error activities and experiences. This situation prevents the hydroforming technology from being adopted further even though the benefits of using hydroforming as an alternative to the conventional stamping is obvious. In this study a finite element based simulation model is developed to investigate the effects of process parameters in a tubular part hydroforming process. The process parameters includes fluid pressure path and axial force path and the curvature of die profile. A simulation model developed for the study is based on an explicit nonlinear finite element code and includes three dimensional modeling of die, blank tube and hole piercing punch. The behaviors of the fluid pressure, axial force and die profiles on the deformation of a complex tubular part are predicted and the design of such process variables is achieved.