The inverse problem to identify the load is normally based on the measurement of frequency response transfer functions. In this paper, the dynamic response due to external load of vehicle structure is described with inverse problem in terms of strain from experimental and analytical response. The function of the practical dynamic load is a combination of the analytical and experimental method with analyzed strain by quasi-static finite element analysis under unit load and with measured strain by strain gage under driving load, respectively. The regularization technique is adopted to alleviate the ill-posedness of the inverse problems. To examine the proposed method, the external load applying on bus frame is identified. The load of bus is identified by the combination of the analytical and experimental method with analyzed strains. In order to get analytical strains, a quasi-static finite element analysis under unit load is performed. Road simulation test is conducted to get measured strains with strain gages. The sparseness and the noise in the measurements should be considered properly in the load identification. In this study, the regularization method is adopted to alleviate the ill-posedness of the inverse problems. This procedure can be used to get the transferred load to use an input data of fatigue analysis for a substructure of which the experimental response is difficult to get directly.