Abstract: The mine MF inductive communication system is analysed and studied, and a new type of MF digital inductive communication system underground is proposed in this paper. In this system, continuously variable slope delta modulation(CVSD) is used to change the analogy signal into digital, GFM is used to modulate the signal, FDMA, PLL frequency synthesizer. This system is provided with good speech quality, simple device and easy realization, good robustness against noise and attenuation, suitable for mine communication.