Abstract: In this paper, it put forward to the resistivity method to monitor the evolution law of coal seam floor fracture zone, analyzed and summarized the general evolution law of fracture zone, built the corresponding geoelectric model. By using the conjugate gradient method, it carried out 3D finite element numerical simulation for geoelectric response characteristics of coal seam floor fracture zone. The simulation results showed that the effect of using resistivity method to monitor the fracture zone was obvious, especially sensitive response to changes in the transverse electrical structure. The evolution situation of fracture zone could be shown clearly in the mining process and the method was helpful to the real-time monitoring and forecasting floor water invasion.