Abstract：By measuring the velocities of the P-wave and S-wave in three orthotropic directions including parallel and vertical directions to the stratum of the rock samples for slate，phyllite，mylonite and metasandstone，and based on the wave velocities of other rocks from the relevant studies，the anisotropic effect of wave velocity ratio of the P-wave and S-wave for most rocks is put forward. The anisotropic effect is controlled by the lithologic characteristics，and apparent for slate and phyllite，while not for the other two kinds of rocks，mylonite and metasandstone. The wave velocity ratio vertical to the stratum of the rock samples is usually less than that in parallel direction，and the relative increment of wave velocity ratio between the vertical direction and the parallel direction decreases as the wave velocity ratio in vertical direction gradually increases. By treating the rock as the transverse isotropic elastic medium and using numerical test of the wave velocity function，the property is theoretically validated.
