Abstract: Aiming at the intensity evaluation of missile launching site,the impulse response model in condition of different structure modulus and thicknesses is built by applying PFWD.According to numerical computation result,the inversion formula of subgrade resilience modulus in elastic semi-infinite body is reformed based on theory of inertial point,and the reformed inversion formula can meet the engineering reality better.The result shows it is feasible to construct nondestructive testing system of intensity parameter of missile launching site with PFWD and realize the fast detection and evaluation of intensity parameter.