The weathering at the top of bedrock in Jurassic coalfield in northern Shaanxi is strong, and the formed weathered bedrock aquifer is the main water filling source of the mine, which poses a serious threat to the safe mining of the mine. The scientific evaluation of the water abundance of the weathered bedrock aquifer and the advanced drainage of the areas with strong water abundance are essential measures for preventing and controlling water disasters of the roof weathered bedrock. In this paper, taking Nanliang Coal Mine as an example, according to the drilling data, the weathering index, core recovery rate, brittle-plastic rock thickness ratio and rock structure index are selected to construct the evaluation system. The fuzzy analytic hierarchy process and coefficient of variation method are used to weigh comprehensively, and the water abundance of weathered bedrock aquifer in Nanliang Coal Mine is evaluated. The results show that the weathering degree of bedrock in Nanliang Coal Mine is strongly affected by ancient terrain, and the underlying Quaternary gully controls the thickness of the bedrock weathering zone. Combined with the evaluation results of mine water inrush status, the water inflow in the water-rich area is large.