A method about multiple-sidebands beat is studied to produce a series of high-power millimeter-wave, and interleaver module is proposed. For the module without additional optical filter and complex circuit driver, periodical sideband signals generated by parameters setting are tunable. Theoretical analysis demonstrates that multiple-sidebands beat with each other, the millimeter wave signal is formed by superposition ultimately, the signal energy is more concentrated, and the frequency is tunable. Simulation results indicate that multiple-sidebands modulation method can generate 12-tupling, 16-tupling, even 18-tupling millimeter waves, and output signals reflect high power characteristics obviously. In comparison with typical bi-sideband modulation method, the power of millimeter wave signal is improved by more than 20 dB. According to the results of the system simulation, the proposed radio-over-fiber (RoF) system has better performance on transmission and anti-dispersion, and it is more suitable for long-distance transmission.