Abstract: With the numerical simulation software of RFPA-FLOW^2D, the water inrush process of minor faults concealed in coal seam floor is analyzed. It shows that there are three stages during the process of seam floor failure under the action of the mine pressure and water pressure, including the active stage, expanding stage and fissure transfixion stage. Due to the simultaneous evolution of floor fracture field and seepage field, the water inrush position can be determined accurately. The simulation results of water inrush induced by several minor faults show that the larger development of concealed minor faults is, the bigger of the failure zone's transfixion strength is, and the easier of the water inrush will happen.