In order to resolve the problem in photonic generation of high -quality millimeter-wave signal,a novel method based on cascaded dual-parallel Mach-Zehnder modulators (DPMZM) is proposed for millimeter-wave signal generation with 16-tupled frequency.Firstly,by contro lling the DC bias voltage,the phase difference of the driving signal and the modulation index of the first DPM ZM,the optical carrier and ±2-order sidebands are suppressed completely,and the ±4-order optical sideb ands are generated.Secondly,this light wave is input to another exactly the same DPMZM,then the ±8-order optic al sidebands and the optical carrier are output.The optical carrier can be filtered out by an optical filter .After beating detection,a millimeter-wave signal with 16-tupled frequency is finally obtained.The theore tical analysis and simulation for this proposed scheme are provided.When the frequency of the RF driving signal is 2.5GHz,40GHz millimeter wave is obtained with a 2.5GHz modulation bandwidth modulator.This technique ha s advantages of high frequency multiplication and high spectral purity.