Water inrush is often encountered during tunnel excavation in karst region, and it will cause the deformation and failure of surrounding rock. So it is of important significance to study the mechanism of water inrush for the prevention of Karst disasters. In this paper, the characters of stress distribution、displacement field and acoustic emission(AE) during the process of water inrush and surrounding rock failure were studied by using RFPA2D (Rock Failure Process Analysis ) software, developed by Center for Rockburst and Induced Seismisity Research of Northeastern University. The results deepen the understanding of the mechanism of water flush and surrounding rock failure caused by gradually increasing hydraulic stress in Karst caves, and it can provide reliable reference for prevention of Karst disasters.