A lead-out end phase-failure protection method for a leakage circuit breaker adopts the following four measures: the first measure is the selection of an acquisition signal, namely, a lead-out end phase-failure current change is acquired as a signal; the second measure is the fabrication of current inductive elements, namely, a plastic loop (4) is used as a core, an enameled wire layer (3) and an insulating tape layer (2) are wound around the exterior of the core, and the two ends of the enameled wire are led out by two insulating leads 1; the third measure is the installation of a leakage circuit breaker with a lead-out end phase-failure protection function, namely, three current inductive elements are respectively arranged on three live wires between a zero sequence mutual inductor (6) and a lead-out column (8) in a common leakage circuit breaker (5); and the fourth measure is the setting of a lead-out end phase-failure protection procedure for the leakage circuit breaker, namely, the current inductive elements collect the current change information caused by the phase failure, transfer to an AD conversion processor and then send to a microprocessor, the microprocessor instructs to alarm and implements break-brake protection after comprehensive analysis. The method solves the lead-out end phase-failure problem that is long for being solved and cannot be solved and fills in the gap in the field of phase failure protection.