A stability improved optical frequency comb (OFC) generation system based on a single integrated polarization multiplexing dual-drive Mach–Zehnder modulator is proposed. Due to the influence of the modulator bias drift on the spectra of the OFC, the amplitude of the OFC spectra would fluctuate with time, which seriously deteriorates the stability of the OFC. The effect of the modulator bias drift on the stability of the OFC is analyzed by theoretical analyses and numerical simulations. A feedback system is proposed to improve the OFC stability. The ratio between the total power of the OFC and the optical carrier power is used as the feedback parameter. In the proof-of-concept experiment, by using the feedback structure, the seven-line OFC stability is experimentally improved from being large than 3 dB within 1.5 h to being below 2 dB more than 4 h.