To overcome the challenges of complex structure and significant control difficulties in conventional optical frequency comb (OFC) generation systems,a novel scheme based on a single-phase modulator was proposed.By driving a phase modulator with two mixed radio frequency (RF) signals,multiple comb lines and high flatness optical frequency combs could be obtained by adjusting only the modulation index and RF signal phase shift.A theoretical model of the scheme was established,and simulation studies were conducted to investigate the effects of the modulation index,RF signal phase shift,and comb line spacing on the flatness of the optical frequency comb.Experimental validation was subsequently performed.The results demonstrate a good agreement among theoretical studies,simulation analyses,and experimental outcomes.Specifically,when the frequencies of the two RF signals are set to f₁ and 2f₁,with a phase shifter (PS) shift of 45°,and a modulation index of 1.431,an optical frequency comb featuring a line spacing of f₁,a flatness of 0.8 dB,and 9 comb lines is obtained,achieving a power efficiency of up to 79.91%.