Abstract: The parameter monitoring system for directional drilling rig in coal mine based on universal PLC controller was developed based on the design ideas of universality, extensibility and modularity. Combined with the practical problems of the matching directional drilling rig, such as complex function, compact layout and limited installation space, the key technologies in the parameter monitoring system are introduced, including key components selection design, explosion proof structure design, system hardware design, system software design. The performance test shows that the parameter monitoring system has stable performance, all kinds of drilling parameters of the drilling rig can be accurately monitored, and the technical specifications meet the design requirements.