Underground water exploration and drainage was a safeguard measure for safe coal mining. The roof of No.15402 roadway in Kaiyuan Mine had the problem of water accumulation in goaf, which brought hidden danger to roadway excavation, and water exploration and drainage measures should be carried out. According to the actual situation of No.15402 roadway in Kaiyuan Mine, a detailed scheme of water exploration and drainage operation was formulated, and the matters needing attention in construction were expounded. After the implementation of the water exploration and drainage scheme, the water discharge and the water pressure of the water exploration and drainage borehole were monitored, indicating that the water exploration and drainage operation achieved the expected effect. And a total of 120,000 m3 of water was explored and discharged, which laid a foundation for the safe excavation of the roadway.