Abstract: In order to solve the problem of long distance of water detection and water release, large construction difficult, long duration and high cost in old goaf, precise directional drilling technology was applied to water detection and water release of old goaf in steep coal seam, the duration and cost of directional drilling technology and drainage roadway technology were compared. The results show that precision directional drilling technology can solve the problem of water detection and water release of old goaf in steep coal seam. Single-hole drilling distance is 712 m. Compared with drainage roadway construction, the duration and cost of precision directional drilling technology can be reduced by about 2/3. Exploration and drainage drilling design should determine the lowest position of the water area as far in advance as possible. Drilling should be along the coal seam roof into the vicinity of the water area from the coal roof into the water area.