Abstract: Based on two cascaded polarization modulators, a stable frequency-sextupled microwave signal generation approach with high spectral purity is presented. Without optical filter, a frequency-sextupled microwave signal of any wave-band was obtained by adjusting the direction of polarizers, the voltage and the phases of radio frequency driven signals. A simulation system was set up based on an OptiSystem platform, and the quality of the generated frequency-sextupled signal, using 4 GHz signal as an example, was verified. Further, the influences of non-ideal radio frequency driven voltage and phases on the quality of the generated frequency-sextupled signal were analyzed as well. The results show that the designed system can generate frequency-sextupled signal with maximum optical sideband suppression ratio and radio frequency spurious suppression ratio of 21.3 dB, 15.2 dB, respectively. In order to obtain the higher quality microwave signal, the non-ideal deviations from ideal driven voltage and phase difference should be controlled within 5%.