The invention relates to a dual-path automatic full-redundancy transparent light transmission system comprising two dual-path full-redundancy optical transceivers. Either optical transceiver comprises two photoelectric conversion interfaces, the electric side of either photoelectric conversion interface is connected with a serial interface which is provided with a control circuit; light signal sides of the two photoelectric conversion interfaces of one optical transceiver are respectively correspondingly connected with optical signal sides of the two photoelectric conversion interfaces of theother optical transceiver; and output ends of sending drivers and input ends of receiving drivers, of the two paths of serial interfaces of one optical transceiver are correspondingly short-circuited. The single-side merging system adopts full-redundancy transparent transmission, and is suitable for a certain special application occasions because the two non-short-circuited data terminals in the mode can not simultaneously send data, but can simultaneously receive data.