A comb line adjustable optical frequency comb (OFC) generation scheme based on 4th power radio frequency (RF) signal and cascaded Mach-Zehnder modulators (MZMs) is proposed. The power operation circuit is used to mix the sinusoidal RF signal;The g enerated power RF signal drives the cascaded MZMs;And a flat OFC with adjustable comb number is p roduced by the cascaded MZMs modulated the input light.The theoretical model of OFC generated by power RF signal driven cascaded MZMs is established,and its performance is studied by us ing OptiSystem.The results show that the comb line interval of OFC is twice the frequency of RF sig nal source,which is tunable and expands the spectrum bandwidth;The target number of comb lines to g enerate OFC is 4 times of the reference modulation voltage,thus the comb lines can be tuned;By adjusting the modulation and bias voltage difference between the upper and lower arms of MZM t o the determined optimization value,the OFC flatness of different target comb numbers can be les s than 0.95 dB.