Abstract: The ultrasonic velocities of two cubic specimens are measured along the horizontal and vertical directions of bedding planes. The measurements reveal that the bedding of the rocks induces clear velocity anisotropy between two orthogonal directions. The wave relocity is faster along the bedding plane than that across the plane in most rock types. A transversely isotropic medium model is established for the rocks. According to the theory of wave crack, the variation rules of wave speed and amplitude, by use of the compressional-wave probe, the polarizing wave speed of rock with large plane is obtained. On the basis of oval hypotheses, isotropy along the bedding direction, anisotropy along other directions and oval change between horizontal and vertical directions, the calculation of dynamic parameters is simplified. A conclusion is drawn that only four kinds of wave speeds are measured by use of P-wave probes to approximately perform inversion of the five parameters of rock with isotropy. It is valuable for the dynamic calculation of rock engineering.