Abstract: As the coal mining depth is increasing gradually,the mine will face the serious threat of the high pres-sure water,mining above aquifer has already become main way in which the deep coal resources are mined.The paper employs RFPA^2D-Flow analytical system to simulate the coal seam floor destructive depth,and educes the 12 m destructive depth of the coal seam floor of mining working face,meanwhile,when coal extraction to 110 m,there is a tundish form to appear in 50 ~80 m range from cutting to driving direction,the destructive area will switch into conduction Ordovician period calcareousness water,and make inrush water from coal seam floor take place.