Abstract: In order to find out the situation of water accumulation in goaf of coal mine and provide basis for the prevention and control of mine water disaster, high density electrical method was used to detect abnormal geology in coal mine. According to the characteristics of high density resistivity method sensitive to water containing water, the forward and reverse calculation of goaf model was carried out by numerical simulation, and geoelectric response characteristics of different goaf were summarized and analyzed, which provided theoretical basis for detecting and analyzing the characteristics of water-accumulated goaf; the abandoned goaf was detected and 9 low resistance abnormal areas were delineated. Combined with the known geology, hydrology, mining data and numerical simulation results, it was speculated that the low resistivity anomalies area 3 and area 4 as well as their corresponding low resistivity anomalies area 7 and area 9 were caused by water accumulated in goaf, and the rest were caused by water-bearing structure. The predicted result is consistent with the actual situation by drilling verification, which further indicates that the high density resistivity method is effective in the detection of water-accumulated goaf.