The invention belongs to the cable channel monitoring system technology field, particularly relates to a cable channel external damage prevention underground sound monitoring early warning application system and aims to protect operation safety and operation stability of an electric tunnel. The system is characterized by comprising a host computer, a monitoring main computer in communication with the host computer, and an underground sound monitoring terminal in communication with the monitoring main computer, wherein the underground sound monitoring terminal is connected with an underground sound sensor, the monitoring main computer comprises a power source conversion and communication pulse generation plugboard, a data acquisition and communication plugboard, a serial port communication plugboard and a bottom board, and the power source conversion and communication pulse generation plugboard, the data acquisition and communication plugboard and the serial port communication plugboard are respectively connected with the bottom board.