The invention relates to a pilot channel transmission device, a pilot channel optical fiber differential protective device and a pilot channel optical fiber differential protective method, and belongs to the technical field of relay protection of electric power systems. The pilot channel optical fiber differential protective device comprises a merging unit, a pilot channel transmission device, differential protective devices, a fault wave recording device, an SMV network switch and a GOOSE network switch, wherein the GOOSE network switch is respectively connected with the pilot channel transmission device, the differential protective devices and the fault wave recording device; the merging unit, the differential protective devices, the pilot channel transmission device and the fault wave recording device are connected to the SMV network switch through an optical fiber interface; the pilot channel transmission device realizes the synchronous sampling of a home station and a transformersubstation on the opposite side, and outputs sampling values of the transformer substation on the opposite side to the SMV network switch; and data with different formats is transformed by using a converter according to requirements, so that manufacturers of the differential protective devices at both ends of a transmission line do not need to be limited, and the compatibility of the protective devices is improved.