Abstract: With the development of large-scale mining activities, the normal fault is prone to slide and instability, resulting in vibration waves, which show significant asymmetric dynamic response characteristics in the areas on both sides of the fault. In order to solve the phenomenon that the “2·22” rock burst accident occurred in Shandong Xin Julong Energy Co., Ltd., the damage area is mainly concentrated in the FD8 fault hanging wall, but almost no dynamic damage in the footwall, it was theoretically analyzed the basic mechanical mechanism of fault plane (belt) isolation, by establishing an energy coefficient model of elastic wave field decomposition at along fault plane, based on the wave field and energy decomposition; numerically simulations for vibration wave barrier of fault plane with different dip angles and different fracture zone thickness were done; and it was also analyzed the activity difference between the two walls of normal fault. The investigations showed that for a relatively isolated normal fault (non fault group), with the increase of fault dip angle, the “transmission” of seismic waves in the hanging wall of the normal fault along the fault plane will be significantly reduced, showing a significant “isolation” characteristic. Also, the activity is different between two walls of normal fault, i.e. the hanging wall slides downward instead of the footwall slides upward. Thus, the dynamic mechanism of the difference between the two walls was revealed. It provides a reference for scientific cognition of the mechanism of normal fault induced disaster, and provides a strategy for the prevention and control of normal fault induced disaster in underground mining