The invention provides an optical signal transmission system and method for a rotary joint. The system comprises a hollow cylindrical rotor, a hollow cylindrical stator, a plurality of groups of photoelectric detectors respectively arranged on the inner cylindrical walls of the rotor and the stator, a plurality of optical signal sources and an optical signal transceiving channel, wherein the light beams emitted by the light signal source reach the corresponding photoelectric detector through the light signal receiving and transmitting channel, and light information is converted into electric signals by the corresponding photoelectric detector. In the optical signal transmission system, optical signals are subjected to duplex symmetric communication, and there is no difference between an uplink and a downlink. The technical scheme can be easily expanded into a multi-channel duplex communication optical signal transmission system, the problems of shaft abrasion and optical fiber coupling of an optical fiber rotary joint are avoided, the communication is reliable, and the working life is long.
Optical signal transmission system and method for rotary joint