In this paper, the finite element model of some car’s body-in-white is established in Hypermesh. The model analysis is executed based on the element model in ANSYS. Through the model analysis the dynamic parameters of the body-in-white are obtained. At the same time，the modal test of a real car body is implemented. The reliability of the finite element model is validated based on the modal test. The results show that the stiffness of the body-in-white is great enough and it can provide optimal design for future designers.