Structure-occupant related method, which uses some structural analysis results for inputs of occupant simulation, has being used widely even if it is difficult to describe real crash precisely. The method is not proper to simulate complex situation such as an occupant behavior restrained with air bag in out-of-position impact. A structure-occupant integrated method is needed to analyze these sophisticated problems in the early stage of design. Therefore, Hyundai Motor Co. tried to develop the method, and the process is described in this paper. The integrated vehicle model includes Hybrid III dummy, air bag, seat belt and interior detail models. The interior detail models are instrument panel, knee bolsters, steering wheel and column, and seats. The part models were compared with the part test results and they were merged into larger models only if they passed correlation test. A finite element sled model was used to investigate the integrated model and the results are well matched with the experimental results.