The utility model discloses a vehicle CAN bus fiber hub, and relates to a serial communicator for information exchange between electronic devices inside the vehicle. The utility model consists of N plastic fiber sending receiving and lossless arbitration circuits I, and signal conversion circuit II. The N plastic fiber sending receiving and lossless arbitration circuits I and the signal conversion circuit II are integrated into a whole by wires. The optical signals from the plastic fiber are converted into electrical signals through plastic fibers, are processed through the wires connected with a photoelectric receiving circuit and the logic operation diode, then converted into electrical signals suitable to plastic fiber sending circuit through a signal conversion circuit, at last converted into optical signals through a plastic fiber sending circuit, then sent to other electronic device through plastic fibers, thereby realizing the plastic fiber transmission of the CAN bus. The utility model uses plastic fibers to replace existing metal twisted pair line, has low cost, increases the date communication rate of CAN bus and the success rate of data transmission, and ensures the real-time performance of data.