A 24 multiplied millimeter-wave signal generation scheme based on cascaded dual-electrode Mach-Zehnder modulator(DMZM), optical delay line and semiconductor optical amplifier(SOA) was proposed. Two DMZMs were cascaded through a tunable optical delay line to obtain high purity ±4 order sideband. Then, the ±4 order and ±12 order sidebands were obtained based on the four-wave mixing effect of SOA. The ±12 order sidebands were selected by a wavelength division multiplexing demultiplexer, and the 24 multiplied millimeter-wave signal were obtained by photodetector. The theoretical analysis and simulation results show that when the input signal is 4~10GHz, a 24 multiplied millimeter-wave signal with the radio frequency spurious suppression ratio (RFSSR) not less than 26dB can be generated, which has high spectral purity and good tunability.