Abstract: According to the complexity of the hydrological conditions of the lower group seam mining in Tuanbai Mine, the water inrush theoretical calculation and t he finite element RFPA2D FEM numerical simulation analysis method of the floor failure process was applied to the comprehensive evaluation on the floor water inrush danger occurred during the mining in the No.11 seam of the lower group in the mine.The study results showed that the sink hole well developed No.11 seam would have a floor water inrush coefficient of 0.05 MPa/m which was closed to the critical water inrush coefficient of the floor structure failure block section. The numerical simulatio n results showed that during the seam mining period, the failure depth in the floor strata was about 15 m and the distance between the failure zone bottom to the roof of the underlying Ordovician limestone aquifer was about 10 m.Based on the above hydrological comprehensive analysis conclusion, the prevention and control counterme asures of the floor water inrush hidden dangers occurred during the seam mining were provided.