Most of auto-body members are composed of stamping parts. These parts have the non-uniform thickness and plastic work hardening distribution during the forming process. This paper is concerned with the side impact analysis of the ULSAB-AVC model according to the US-SINCAP in order to compare the crashworthiness between the model with and without considering the forming effect. The forming effect is calculated by one-step forming analysis for several members. The crashworthiness is investigated by comparing the deformed shape of the cabin room, the energy absorption characteristics and the intrusion velocity of a car. The result of the crash analysis demonstrates that the crash mode, the load-carrying capacity and energy absorption can be affected by the forming effect. It is noted that the design of an auto-body should be carried out considering the forming effect for accurate assessment of crashworthiness.