The utility model provides an electric track feeder protecting device, composed of an AC input circuit, a switching value input circuit, a feeder protection circuit, a signal outlet circuit, a power supply circuit, an interface circuit, an alarm circuit, etc. The utility model is characterized in that the feeder protection circuit is a plug-in unit which is at least composed of a single-chip computer CPU, a programmable timer / counter, a programmable I/O interface, a programmable data memory, a fixed value memory, and a program memory. The programmable I/O interface, a timer, and each memory are connected with the single-chip computer CPU by the data bus and the address bus which are arranged in the plug-in unit. The utility model has the advantages of strong anti-interference ability, and short handling time of hardware faults, and can simultaneously provide protection and distance measurement for multiple leading lines.