Abstract: The authors used the Analytic Hierarchy Process (AHP) in the researches of coal seam floor water irruption.Taking Feicheng Mining area as an example,the authors discussed the method of comprehensive assessment of coal seam floor watre-irruption factors,which makes the researches from qualitative analysis to quantitative analysis,and will give a good deal of guidence to the investigation on the hydrogeologic coal condition and prediction of coal seam floor water-irruption.