Abstract: In view of problems of distorted voice, missing broadcasting, single function and incompatible with other system existed in current voice communication system used in underground coal face, hardware and software design schemes of a mine-used voice communication host based on Modbus RTU protocol were proposed. The host can not only control internal stored voice broadcasting through switching value which is compatible with active and passive input, but also control voice broadcasting of voice synthesis chip and power amplifier circuit by Modbus RTU protocol. External audio signal can be accessed to the host and broadcasted timely through the power amplifier circuit when it is detected by audio detection circuit. The host meets requirements of underground voice communication between different systems.