Abstract: Aiming at the higher requirements of coal mines for the drilling borehole trajectory construction quality, in the process of drilling construction, because of the influence of earth gravity, rock factor and process technology, the drilling borehole trajectory will drift. A design scheme is proposed based on electromagnetic wave transmission parameters measurement while drilling, the drilling pipe is taken as the transmission medium, and MWD parameters will be sent to the host in the form of electromagnetic waves. It is given that the whole design scheme of the system, the signal transmission and processing method, the hardware circuit design of signal sending and receiving, and software management flow. The application status of prototype shows that the prototype can accurately transmit parameters of drilling bit to the host, and can real-time display trajectory parameters of borehole, timely to know the situation of drilling construction. It can guide the staff manner to adjust the bottom hole assembly and drilling parameters in time, so that the drill can extend according to the predetermined direction, which can save a lot of manpower and material resources, and has obtained excellent economic benefits.