Abstract: Goaf water is an important type of mine water disaster, causing serious accident. Use of directional long borehole to detect and drain goaf water is an important innovation for coal floor water prevention. By combining directional drilling technology with conventional rotary drilling technology, this paper systematically studied the detection and drainage of goaf water by directional long borehole, drilling equipment, borehole design, drilling technology, directional drilling technology and equipment. The tests in Baijigou mine show that the drilling technology and equipment are reliable and advanced, the effect of detection and drainage of goaf water is good. The research results enrich and improve methods for goaf water prevention, it is significant for safe and highly efficient mining.