The invention relates to a safety isolation system and method for transmission of a power system under a multi-service optical network. The system includes a local device and a remote device which communicate. Both the local device and the remote device include at least two ports, an optical buffer, and a multi-light path selector which are successively connected, and also include an optical buffer controller which controls the optical buffer and a multi-light path switching synchronous controller which controls the multi-light path selector. According to the invention, the technical solution meets requirements for mutual transmission among different systems of an intelligent power grid, and also meets safety requirements. The safety isolation transmission method for optical transmission under a safe level service environment, realizes data transmission among safe level services systems without having to modify network infrastructure, and meets requirements for physical safety isolation.