The invention discloses a cable joint crack positioning device based on a sound wave signal, and the device comprises a carrier body, a sound wave collection module, a signal line and a positioning terminal, wherein the carrier body is laid along a high-voltage cable power transmission line. The sound wave collection module is disposed on the surface of the carrier body, and is used for collecting the sound wave signal which is coupled to the carrier body during cable joint crack and is transmitted along the carrier body. The signal line is disposed in the carrier body, and is used for the signal transmission between the sound wave collection module and the positioning terminal. The positioning terminal is disposed in a station duty room, and carries out the quick positioning of a cracked cable joint according to the difference of moments when the sound wave collection module receives a crack sound wave signal at different positions. The device can carry out the quick and accurate positioning of the cracked cable joint, and greatly reduces the loss caused by a fault. The device can carry out the quick and accurate positioning of the cracked cable joint, and greatly reduces the loss caused by a fault.