A novel method is demonstrated to tunably compensate dispersion effect in phase modulated radio over fiber (RoF) links using an optical carrier Brillouin processing technique, which is based on stimulated Brillouin scattering (SBS) to control the phase shift of optical carrier in the modulated lightwave signal. Since this phase shift can be dynamically tuned, frequency response can be tunably improved. Both simulation and experimental results show that a uniform frequency response ranging from 1-12 GHz with a fluctuation of less than ±1 dB can be obtained by an optimal phase shift on the optical carrier.