The utility model provides an overhead line fault detector, and an overhead line fault detector with a wireless public network communication function, the overhead line fault detector is installed at phase lines of overhead lines in a medium-voltage distribution network, and comprises a wireless public network communication unit, a central processing unit comprises a wireless public network module interface circuit, the wireless public network communication unit is connected with the wireless public network module interface circuit of the central processing unit, and data and signal exchange is performed; the wireless public network communication unit is used to communicate with a main station system, and transmit data and signals transmitted from the central processing unit to the main station system in a remote way; and electricity is taken via load induction and is supplied via in-built dry cells. functions of short circuit and earth fault detection and on-site indication, load acquisition, voltage acquisition, and high voltage live display of the medium-voltage distribution network overhead line are realized, and therefore, the wireless public network communication unit is used for the internal of the fault detector, under the condition of not increasing an external communication terminal, wireless communication with the distribution network main station is realized.