Abstract：In orter to exactly predict risk the of water inrush on coal floor, using five figures and double coefficients method, based on data from the No.8 coal mine of Pingmei, the risk of the Cambrian limestone water inrush on 21 coal floor was forecasted and assessed.By analyzing the relationship between the impermeable layer and the water pressure, the pressure coefficient and water inrush coefficient were gotten.Then contour maps of hydraulic pressure on coal floor, thickness of effective water-resisting layer, water inrush coefficient and the partition map of water inrush risk were drawn by using Surfer software.The result showed that the water inrush risk of the mining area in the northwest and northeast was relatively larger than the others, but the area was relatively smaller.There are two small areas in the south and central, which belong to the level of basic safety.The rest of mining area belongs to the level of small water inrush risk.Overall, the Cambrian limestone water inrush risk on 21 coal floor of No.8 coal mine in Pingmei is relatively small.

Keyword：five figures and double coefficients method;the Cambrian limestone water;mine water inrush;partition evaluation;