Abstract: The coupling of mathematical equations was substituted by coupling of physical process,and the basic governing equations of fluid domain,solid domain and fluid-solid interface were deduced respectively for flow-blade interaction system.Furthermore,the numerical method was given through bidirectional sequential method,and the corresponding physical process of blade vibration from unsteady to steady state was described.Finally,certain engineering sample was discussed to verify the method,and the dynamical responses of certain secondary stator used in a missile engine were obtained.Thus the characteristics of flow field and stress distribution on stator were gained,and the advantages of sequential method on solving fluid-solid interaction(FSI) problems were pointed.