Abstract: Directional drilling technology is effective method of deep borehole consequent landside drilling in underground coal mine. In order to ensure the safety of roadway excavation, Zhangji Coal Mine introduced this technology to construct detecting and releasing water boreholes for limestone consequent landside. There were 3 boreholes, designed at the bottom of tape machine lane, and the scope of protection was 40 meters covering the left and right sides of designed roadway. Through the field application, No.1 borehole was finished with the depth of 518 meters, No.1-1 borehole was finished with the depth of 483 meters, No.2 borehole was finished with the depth of 558 meters, and there was no formation of water. This successfully achieved the purpose of protecting roadway excavation, and summed up some experiences, such as the exploration progressive drilling method of “lithologic changes in drilling, geological data judgement, drilling direction guidance, and geological data correction”, “directional drilling & composite drilling” control layer drilling method, open branch skill of hard rock low speed grinding and so on. Directional long boreholes for consequent landside are used to replace the ordinary boreholes for detecting and releasing water and became the new technology of protecting roadway excavation boreholes construction for detecting and releasing water.