The invention relates to the relay protection field, and discloses a zero-power protection method and apparatus for a power generation system. The zero-power protection method comprises the steps of receiving the active power of a monitored generator, and comparing the active power of the generator with a preset power high value and a preset power low value separately; and if the active power of the generator is greater than the preset power high value, and the active power of the generator is lower than the preset power low value after a preset duration, performing zero-power protection on the power generation system. By adoption of the zero-power protection method, zero-power protection can be carried out in time for the power generation system in case of faults so as to prevent power plant equipment from being damaged.