In order to improve the flexibility of the communication system, expand the application range and reduce the construction cost, a full-duplex radio-over-fiber system with multi-band signal output is proposed in this paper. Under the condition of single light source, this paper realizes the downlink vector signal transmission in three different frequency bands by flexibly controlling the angle of polarization controller and linear polarizer. Using carrier reuse and coherence detection technology, uplink baseband signal output is realized. The simulation results show that for the 6 Gb/s hexadecimal quadrature amplitude modulation(16QAM) signals are transmitted through 30 km optical fiber, the minimum error vector amplitude(EVM) of the output signals in 5 GHz, 45 GHz and 25 GHz bands in the downlink are 5.66%, 4.03% and 2.67%, respectively. The minimum EVM of the uplink output signal is 4.01%.