A novel full-duplex radio-over-fiber (ROF) system based on optical phase modulator(OPM)and fiber Bragg grating (FBG) filter is proposed and analyzed theoretically.In the center sta tion,double sideband with the suppressed first-order sidebands optical millime ter (mm) wave signal are generated utilizing pha se modulator along with FBG filter,while 2.5Gbit/s downlink signal is modulated only onto central optical carrier sign al and transported along the optical fiber.In the base station,the unmodulated sideband is reused to transmit the uplink signal. The paper sets a theoretical model about optical mm-wave generation and analyzes fiber dispersion influence on phase,an d proves the feasibility of the system through the simulation test.The results show that both the upstream signal and the downstream signal are visible in eye diagrams after 60km fiber transmission.The power penalty of the upstream signal is less than 0.2dB and the power penalty of the downstream signal is less than 1.8dB.The system possesses better anti-dispersion performance.