Abstract: To study the mechanism of water inrush in coal mine under the condition of fracture zone, a series of indoor tests of water inrush are carried out by using the self-developed particle migration test system of fractured rock mass, and the variation law and influencing factors of particle migration on the hydraulic characteristics of sandstone in fracture zone in the process of water inrush are discussed.The results show that the permeability of crushed sandstone can be divided into four stages, which oscillatory growth stage, rapid growth stage, slow growth stage and stable stage.The initial porosity and water pressure have a great influence on the final permeability and porosity of the sample.The numerical simulation shows that the particle movement direction is generally towards the fracture direction, accompanied by local eddy current phenomenon.The migration and discharge of particles are the essential factors leading to water inrush in fractured zone.The research results further deepen the understanding of coal mine water disaster under the condition of fracture zone, and have a certain supplementary effect on the occurrence mechanism of water inrush.