An optical frequency comb generation scheme based on cascaded phase mo dulator and optical attenuator is proposed.The theoretical model of the scheme is establish ed and verified systematically.Finally,the effects of radio frequency (RF) signal amplitude and optical attenuator attenuation coefficient on the flatness of optical frequency comb are studied.T he results show that the numerical calculation is in good agreement with the experimental results.By adj usting the amplitude of RF drive signal and the attenuation coefficient of optical attenuator,a high -performance optical frequency comb with 15 comb lines,0.8 dB flatness and 5.05 dB side-mode suppres sion ratio (SMSR) can be generated.After the filter is introduced into the scheme,the flatness and SMSR can be increased by 62.5% and 61.4% respectively on the premise that the number of comb lines remains unchanged.