Abstract: In order to mine Ⅱ₁ coal seam in Pingdingshan No.5 Mine safely, through the comprehensive analysis of mine geology and hydrogeological conditions, we select hydraulic pressure and watery of Cambrian limestone aquifer, the equivalent thickness and the thickness of brittle rock of effective confining bed and fault fractal dimension as the main factors for water inrush of floor, and adopt IFAHP to determine the weight coefficient of each main factor, and establish evaluation model of water inrush from coal seam floor and divide the risk of water inrush. The results show that water inrush risk enhances firstly and then weakens from east to west, and the water inrush risk index of Ji₄ panel is very high.