Seismic wave induced by blasting influences geomaterials of slopes significantly. The dynamic stress and vibration characteristic of geomaterials in slopes far away from the blasting location were analyzed based on a simplified mechanical model and stress wave theory. The dynamic tangential stress σxx (parallel to the slope surface) decreases rapidly with the increase of the depth. The dynamic normal stress σzz and the dynamic shear stress σzx (vertical to the slope surface) are zero on the surface, and they increase rapidly firstly and then decreases slowly with the increase of the depth. When the depth z=0, the tangential vibration velocity vx and the normal vibration velocity vz are at their peak, which decrease rapidly with the increase of the depth. The analytical solution of the depth zcr is deduced at which the peak value of σzz and σzx is located. The weaker the geomaterial and the higher the frequency of the vibration, the less the zcr value become. When the vibration velocity and vibration frequency are the same in different geomaterials, the maximum dynamic stress in the weaker geomaterials is smaller than in stronger geomaterials. When the vibration velocity is the same, the maximum dynamic stress is the same in the same geomaterials, its depth is related to the vibration frequency, and the higher the frequency, the smaller the depth. In order to determine the dynamic load in quasistatic analysis of slope dynamic stability, an analytical method for calculating the dynamic stress on the potential sliding surface of the slope is proposed through the monitored vibration velocity.