An optical power compensation method and a device relating to the communications field comprises: a first node that obtains a first optical power and a first timepoint, receives at least two second optical powers sent by a second node, obtains second timepoints corresponding with the at least two second optical powers, where the second timepoint is a timepoint at which the first node receives the second optical power, and determines a target timepoint from the second timepoints according to a preset delay and the first timepoint. The first node determines a variation of a span loss according to a target optical power and the first optical power, where the target optical power is a second optical power corresponding to the target timepoint, and adjusts a gain value and/or an attenuation value of the first node according to the variation of the span loss.