Abstract: For shortcomings of mine-used broadcasting systems of traditional constant-pressure broadcasting, local amplified phone and personal access system, the paper proposed a design scheme of underground digital security broadcasting system and introduced whole structure and design methods of hardware and software of the system. The system can realize remote audio transmission at lower speed, which adopts audio encoding method of Ogg Vorbis and CAN bus to transmit data. The application results showed the system has better ability of audio restoration.