The invention provides a coal mine used caterpillar-mounted full-hydraulic underground drill hydraulic system. The prior caterpillar-mounted full-hydraulic underground drill requires a plurality of hydraulic control valves or to add a change valve in the hydraulic system in order to protect the thread of the drilling tool when the drilling tool is lifted or lowered quickly, or wrenched and disassembled, which causes not only complexity of the hydraulic system and low reliability, but also the trouble to operate and control the system and low control accuracy. The invention is designed to solve the problems. The caterpillar-mounted self-propelled underground drill hydraulic system provided by the invention comprises a caterpillar traveling loop, a unit head gyration loop, a feeding pulling loop, a drill stabilization and angular adjustment loop, and has the functions of linear traveling of the drill, turning on site, stopping on a ramp, gyration and feeding of the unit head, linkage of a feeding oil cylinder, a chuck and a clamper. In addition, the invention has the functions of hydraulic feedback control and linkage. Accordingly, the hydraulic system provided by the invention has the advantages of handiness, convenience for control, high control accuracy, quick response, etc.