Abstract: In view of problems of deficiencies in real-time display and centralized storage of drilling parameters of full hydraulic directional drilling rig in coal mine tunnel, a drilling parameters monitoring system of directional drilling rig in coal mine tunnel was designed. Distributed design is adopted in the system, and data transmission and communication are realized by CAN bus, while key drilling parameters can be monitored and displayed in real time, such as drilling speed, drilling/drawing pressure, speed, torque, water pump flow and pressure. Data transmission and centralized storage are carried out through explosion-proof computer, which can facilitate analysis and adjustment of drilling parameters. Precise measurement and control of drilling construction can be realized by combining pressure sensor, flow sensor, etc. The field application results show that the system can be used with various types of directional drilling rigs, and can monitor and display various drilling parameters of directional drilling rig in real time and accurately. The desgin of the system has laid a foundation for the follow-up realization of "mechanical-electric-hydraulic" integrated control and fault diagnosis of directional drilling rig in coal mine tunnel.