Due to the recent development both in the numerical simulation technology and computer technology, the role of numerical simulation in sheet forming industry has been continuously increasing in recent years. This paper describes the application of numerical simulation technology in the forming process of a complex box-type part with Dynaform and gives a fairly accurate forecast of defects that may appear in the forming process. Prediction of the effect of design parameters such as blank holding force and drawbeads on forming quality is investigated. The study indicates that blank holding force and drawbead directly affect the metal flow and formability of stamping. Then, by adjusting blank holding force and setting appropriate drawbeads, an optimized stamping process plan is obtained and is validated in experiments. Finally the phenomenon and displacement of distortion springback are predicted in the springback simulation, which is useful to further improve the quality of this kind of part.