A method of using radio frequency (RF) control signal to achieve multi-wavelength fiber laser output precisely tuned is proposed. 65 wavelengths simultaneously tuned precisely is achieved by placing a RF controlling single side band (SSB) modulator outside the cavity of multi-wavelength fiber laser. The multi-wavelength output can be tuned simultaneously with a tuning step ranging from 150 MHz to 14 GHz when changing the frequency of RF signal, corresponding to 1.2 pm as a minimum tuning step. The tuning resolution is determined by the resolution of the RF wave generator, which can be as low as 1 Hz. The wavelength spacing remains 50 GHz before and after the multi-wavelength tuning. The sideband-mode suppression ratio (SMSR) of each wavelength output can reach 20 dB.