A wideband frequency-tunable optoelectronic oscillator(OEO) is design ed based on carrier phase-shifted double- sideband modulation (CPS-DSB) system,which consists of two 3dB couplers,a π- bias Mach-Zehnder modulator and a variable phase shifter (VPS).Furthermore,a tunable microwave photonic filter ( MPF) can be implemented by a carrier phase-shifted double-sideband modulation (CPS-DSB) system and a linear chirpe d fiber Bragg grating (LCFBG).By simple adjusting the phase of the VPS,the central frequency of the MPF is changed and the oscillation frequency of the OEO can be tuned.A detailed theoretical analysis is performed,which is verified by simul ations.A large frequency-tunable range can be achieved by tuning the pha se of the VPS.