Abstract: The paper analyzed disadvantages of existing dispatching telephone system in coal mine, introduced a design scheme of broadcast telephone system based on Sunplus SPCE061A single-chip microcomputer and CAN bus. The system uses Sunplus audio compression coding algorithm library to realize a voice compression coding in 10~24 kbit/s, so as to get voice data with middle and low rate which fits transmission in CAN bus. For received voice data, the system uses relevant voice decoding algorithm to decode real-timely and then sends them to amplifier module to drive loudspeakers. The testing result showed that the system is reliable and stable with long transmission distance and high voice quality. It supplies a new solution to the problem of real-time in existing voice communication system in coal mine.