In order to analyze the failure depth of the floor strata during the mining of the lower coal seam in the close distance coal seam of Zhengli Coal Industry and prevent the water outburst accident of the coal seam floor, boreholes were arranged in No.4-1051 Face of the mine, and electrodes were installed in the boreholes. The depth of the floor failure zone of the lower coal mining in the close distance coal seam group was explored by direct current method. The exploration results showed that after the mining of No.4-1 coal seam in the upper part of the close distance coal seam group, the depth of the coal seam floor failure zone in No.4-1051 Face was 23.7 m when No.4 coal seam in the lower layer was mined, which provided a basis for the risk assessment of water outburst from the Ordovician limestone aquifer in the coal seam floor during the subsequent mining process and the formulation of water prevention and control measures.