The invention discloses a power leakage protection method which comprises the following steps: S1) obtaining the instantaneous parameter of the remaining current from a main circuit; S2) according to the instantaneous parameter, calculating the phase angle of the remaining current; determining whether the phase angle jumps from the previous cycle or not; S3) if the phase angle jumps from the previous cycle, determining whether the phase angle is within the capacitive phase angle range or within the resistive phase angle range; if the phase angle is within the capacitive phase angle range, returning to the step S1; if the phase angle is within the resistive phase angle range, then proceed to step 4; S4) determining whether grounding impedance is reduced or not in a preset duration; S5) if the grounding impedance is reduced, starting protection to the remaining current; if the grounding impedance stays unchanged, then executing the step 6; and S6) determining whether the sudden change amount of the remaining current exceeds the set value or not; if the answer is yes, starting protection to the remaining current; and if the answer is no, returning to the step 1. In addition, the invention further discloses a power leakage protection system and a remaining current protection breaker which could achieve the same technical effects as the above.