This research examines the behavior of dry sand and sand pile under the forcing of horizontal vibration. Another subject , we use steel spheres to simulate the unstable condition of sand-pile slope. In the case of horizontal vibrations , The thickness of fluid layar near the surface , H , is propotional to the dimensionless peak vibrational acceleration G and size(length) of the sand box. In the case of sand-pile , there are two types of motions. Initial sand surface collapse and submoving layer. The moving velocity of the surface collapse is faster than the velocity of the moving layer. The moving velocity is propotional G. In the experiment of slope stability , we use steel sphere to simulate the grained stucture of pile surface. Square surface stucture of pile is more stable than triangular surface structure , but in the natural fact ,surface structure of pile is nearly triangular. This research examines the behavior of dry sand and sand pile under the forcing of horizontal vibration. Another subject , we use steel spheres to simulate the unstable condition of sand-pile slope. In the case of horizontal vibrations , The thickness of fluid layar near the surface , H , is propotional to the dimensionless peak vibrational acceleration G and size(length) of the sand box. In the case of sand-pile , there are two types of motions. Initial sand surface collapse and submoving layer. The moving velocity of the surface collapse is faster than the velocity of the moving layer. The moving velocity is propotional G. In the experiment of slope stability , we use steel sphere to simulate the grained stucture of pile surface. Square surface stucture of pile is more stable than triangular surface structure , but in the natural fact ,surface structure of pile is nearly triangular.