Using acceleration mobility of a single degree freedom springmass vi b ration system (mass and damping neglected) as evaluation criteria, this paper pr esented an acceleration mobility frequency response analysis method to evaluate the dynamic stiffness of engine mounting points on a car body. A series of finit e element models were constructed for a car body, the engine mounting brackets, the coupled acousticstructure in the body inside cavity. The static stiffness a nd dynamic stiffness of the engine mounting points were comparatively studied，w hile the sound pressure response to driver’s ear with unit harmonic load applie d on the mounting points was calculated, in order to study the impact of dynamic stiffness on the body. The result shows that the dynamic stiffness analysis is consistent with that resulting from the static stiffness and acoustic response a nalyses，therefore, the proposed method can be used to comprehensively evaluate the body’s performances on dynamic stiffness and NVH.