The invention relates to a rapid switching mode variable impedance transformer adaptive current protection method, characterized by comprising the following steps: 1) measuring the real-time three-phase voltages Ua, Ub, and Uc as well as the three-phase currents Ia, Ib and Ic at the wire inlet end of the transformer; then, using the symmetrical component method to convert the A-phase voltage and current, B-phase voltage and current and C-phase voltage and current into positive/negative zero-sequence voltages and currents; and 2) using the fault component method; based on the positive/negative zero-sequence voltages and currents in the normal state and the positive/negative zero-sequence voltages and currents in the fault state, calculating the fault components of the positive/negative zero-sequence voltages and currents. The protection method, through the real-time rectification of the current values, can meet the requirement for the sensitivity of a backup protection system so as to well address the problem that traditional protection is insufficient in sensitivity.