We consider the effect of the impinging of a plane wave on a surface of a stratified media at two different angles of incidence. The Goupillaud's equal-traveltime layer model and it's exact inverse formulas[1] are used, the time sequence of the video impedances can be computed.In order to compute the deepness distribution of the densities and velocities for the layered media, we propose in this paper "The contrast method of the layer-interfaces", by which, the computational experiments were made and the numerical results are satisfactory.