The invention relates to a method and a device for determining a coal bed bottom plate grouting target region based on fuzzy layer analysis. According to the method, a comprehensive water-resisting property evaluation subsystem is built based on main control factors of bottom plate rock layer water-resisting properties, weights are given to the main control factors by a fuzzy layer analysis method, interaction and combined effect between indexes are comprehensively considered, a uniform judgment method of the grouting target region is built, discovery of the grouting target region has operability, popularization is facilitated, acquired geological data can be sufficiently used, and the position of the target region can be more accurately judged.