Abstract: Coal mining practices in the northern China coal field face severe water inrush problems. Taking the influence of many factors on the occurrence of floor water inrush into consideration,a water inrush risk index method based on the fuzzy Delphi analytic hierarchy process (FDAHP) and the technique for order performance by similarity to ideal solution (TOPSIS) was put forward to evaluate floor water inrush risks. A case study was carried out for the Ordovician limestone water inrush risk assessment of the No. 11 coal seam floor of the Liangzhuang Coal Mine and Suncun Coal Mine in the Xinwen coal field,Shandong Province. Seven main control factors,including fault intensity index,density of fault endpoint and intersection,water pressure of aquifer,water abundance of aquifer,thickness of water-resisting layer,ratio of brittle rock,bottom damage depth,were selected as decision indexes for the water inrush risk assessment of the No. 11 coal seam. The FDAHP method was used to distribute the weight vector. Based on the TOPSIS method,the safest and most dangerous solutions of the water inrush in the study area were analyzed and the water inrush risk index method was finally established. The reliability ofthe model was verified and the zoning threshold was determined. The results show that the water inrush risk index is higher in the northeast of the study area,indicating larger possibility of water inrush.The water inrush risk index in the southwest of the study area is lower,indicating smaller possibility of water inrush. The predictions of the water inrush risk index model based on the FDAHP and TOPSIS methods are consistent with engineering practice.