Only a few boreholes in Beijing Daanshan Coal Mine were controlled to the level of +550m. In order to explore the occurrence conditions of deeper coal seams and improve the magnitude of order of resource reserves, a ZDY1000G full hydraulic tunnel drill rig and S75 wire-linecore drilling technology were used to carry out deep hole drilling in the adit. The test drilling depth in the tunnel was 505.17m. Subsequently, from 2012 to 2014, the total drilling amount was 8237m, resulting in an increase in the resource reserves by 18.777 million tons through exploration . On the one hand, the deep hole drilling technology can accelerate the exploration of deep horizontal coal seams, and define the occurrence condition of deep horizontal coal seams, which provide reliable geological data for the development of the project. On the other hand, it also reduces the cost of tunnel exploration and improves the efficiency of development. In this paper, the deep hole drilling in the tunnel is introduced.