Based on the software NX Nastran,the Cabin Cage finite element model was established,using beam,plate,solid and mass element properties. The structure’s max deformation and max stress were counted out,and an experiment was did to confirm the accuracy of the finite element model. Based on the simulation results,the authors optimized some part of the structure and did another simulation. The further results showed that the stiffness and strength of the optimized structure had been improved significantly. This modeling method with serious kinds of element properties can be widely applied in design and optimize of large-scale structures.