Abstract: For the mine that mining under safe water pressure of aquifer with Ordovician limestone water on the floor, the exploration and treatment of the hidden water diversion structure in the mining process is the focus of water disaster prevention and control. Taking the water hazard exploration and treatment project of No.6 upper coal seam two-level auxiliary transportation roadway driving through DF6 stepped fault zone in Huangyuchuan Coal Mine as an example, by means of drilling, geochemical prospecting and outflow test, it is found that DF6 fault zone is a stepped fault zone composed of multiple faults. The fault zone is rich in water and is replenished by Ordovician limestone water from the floor. Using the method of advanced drilling combined with curtain grouting, 15 grouting treatment boreholes and 3 inspection holes were constructed to treat the DF6 fault zone in front of the smooth excavation of No.6 upper coal seam two-level auxiliary transportation roadway. The treatment effect is good, which effectively ensures the safety of the excavation of No.6 upper coal seam two-level auxiliary transportation roadway through the fault zone.