It is very important data to analysis the deformation(displacement) and design protection that forecast the change of rock mass deformation modulus and relaxing band thickness after the rock slope high excavated. The dynamics of wave studies relation betweenaverage stress and bulk modulus, the longitudinal wave speed of rock mass and elastic modulus, deformation modulus. By these results, the paper gains the relation the relation between the longitudinal wave speed of rock mass and rock mass deformation modulus, the stress of rock mass, studies the change of deformation modulus afterrock slope excavated, predicts the thickness of rock mass relaxing band though field data and finite element analysis.