Abstract: Through the establishment of geophysical numeric model of rock deformation and failure of coal floor in mining, the characteristics of resistivity variation of destruction zone in coal floor were analyzed by using forward calculation, WBD field monitoring was carried out in the workface of No.5 coal mine. Simulation data and field detection results show that the coal floor resistivity value is closely related with the mining process. High resistivity anomalies appeared behind the workface, the high resistivity anomalies corresponded with the location of deformation and failure of floor. In front of workface low resistivity anomalies appeared, and coincided with the high stress area caused by mine pressure. Along with advance of workface, the resistivity anomalies will be synchronously changed. According to the regularities of floor rock resistivity change, and combined with the hydrogeology characteristics, the dynamic exploration of resistivity method can study the regularities of coal floor deformation and failure and is useful to predict water inrush in floor.