Abstract: In order to research the disturbance and destruction mechanism of the the fracture zone around collapse column caused by the dynamic pressure,the FLAC^3D software was used to simulate the variation of the horizontal stress and distribution of plastic zone in fracture zone with the advance of the working face.The numerical simulation results provided that the cracks in the fracture zone around collapse column easily occurred crack propagation and coalescence which may lead to water inrush.The results showed that crack was propagation and coalescence due to the reduce of horizontal stress,which may lead the fracture zone to be dominant channel for mine water-conducting.