We will analyze the large deformation of a shock-absorbing structure to prevent the fracture of an elderly person falling. However, in order to analyze the coupled phenomena between the structure and air with large deformation, it is necessary to consider the discontinuity of mass density and velocity field at the interface between solid and fluid, which has not been applied in previous studies. In this study, we propose an Eulerian method for structure-fluid interaction analysis that can be applied stably even in the presence of discontinuities in the mass density and velocity fields at the interface, and verify its validity and effectiveness through massively parallel simulations using a supercomputer.