A photonic approach of frequency-sextupling microwave signal generatio n by cascading a polarization modulation (PolM) and a dual-parallel Mach-Zehnder modulator (DPMZM) is theo retically proposed and experimentally verified.Optical sidebands are generated under the condition of radio frequency (RF) signal modulation.By adjusting the polarization controller (PC) before the p olarizer and analyzer,only odd-order sidebands are kept.Then going through the DPMZM,one of the sub MZMs is modulated by RF signal,in the maximum transfer point (MATP).The other sub MZM is not modulated.The firs t order sidebands are suppressed, so that the third order sidebands are preserved.A frequency sextupling microwav e signal can be obtained by beating the two third order siandbands at the photodetector (PD).The simulatio n results show that the radio frequency spurious suppression ratio (RFSSR) is as high as 34dB under the condition of ideal extinction ratio (100dB) without any optical or electrical filter.Even if the extinction ratio is 30dB,the RFSSR can still reach 21dB.Both theoretical analysis and experimental results verify the feasibility of the proposed scheme.