Numerically analyzed is the transmission performance of the optical millimeter (mm)-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber. 60 GHz mm-wave sub-carrier(SC) signals can be obtained after fiber transmission, simultaneously, the phase-modulated signals can be converted to the intensity-modulated ones. The numerical results show that the optical mm-wave at fading loops has better performance, and the eye diagram still keeps open when optical mm-wave signal is transmitted over 98 km.