Abstract: Sub horizontal long hole drilling technique is an important approach to improve the efficiency of gas drainage and ensure safe mining in underground coal mines. Drilling rig is the main drilling equipment to realize the pivotal technique. The development of the track-mounted ZDY6000LD (A) hydraulic directional drilling rig is introduced in this article, including the position, track-mounted, main structure and hydraulic system. Underground test proved that the rig is suitable to drill branched boreholes of more than 1000 m, reliable in performance, high in precision, stable, fast and convenient in movement.