Abstract: In view of the limitations of the evaluation method of hydraulic fracturing effect of coal mine roof in terms of spatial continuity and real-time dynamic feedback, this study proposes and systematically applies the high-density electrical method to dynamically and quantitatively evaluate the hydraulic fracturing effect of coal mine roof. Through high-density electrical detection and resistivity tomography technology, the dynamic change of resistivity of coal and rock mass caused by fracture generation and fracturing fluid seepage during fracturing is monitored in real time. The engineering practice was carried out in the 112205 working face of Xiaobaodang Coal Mine in Shaanxi Province. The continuous apparent resistivity detection before, during and after fracturing was carried out for the staged fracturing process of XBD-02L horizontal well, and the quantitative evaluation index of fracturing effect ρ _ SL was innovatively proposed based on the resistivity change. The detection results show that the effective influence range of fracturing can reach 200 m in the horizontal direction and 57 m in the vertical direction, and the fracturing fluid presents a dynamic process of ' diffusion-loss '. The application effect is effectively verified by the distribution results of the water-rich area detected by the audio electro-penetrating perspective and the monitoring data of the mining pressure in the working face. The high-density electrical method can realize the visualization, dynamic and quantitative evaluation of the fracture network development and fracturing fluid migration range of roof hydraulic fracturing, which provides an important technical means for optimizing fracturing design and ensuring safe and efficient mining of coal mines.