A zone selective interlocking device includes a first port, a second port, an input bus, an output bus and a query signal receiving branch. The first and second port each are switchable between two states, connected to the input bus and connected to the output bus, and the zone selective interlocking device is operable in a first mode. In the first mode, the query signal receiving branch is turned on. Within a preset timeslot, a link fault query signal is permitted to be inputted to the query signal receiving branch through the first port, while a link fault query signal is prevented from being inputted to the query signal receiving branch through the second port. Based on whether a link fault query signal is received within the timeslot, a judgment is made on whether a fault has occurred in a communication link connected to a corresponding port.