Abstract: In view of problem of poor emergency communication performance of existing underground communication equipment, based on analysis of requirements of distributed communication technology applied in underground and comparison of performance of current four distributed peer to peer network models, a scheme of underground distributed peer to peer communication technology combined SIP protocol and fully distributed peer to peer network technology was proposed. Signaling flow, call processing between caller and callee, distributed interaction mechanism and datagram design of the scheme were described. The test results show that the scheme is a good solution for underground terminal communication in out-of-service situation.