A digital pulse width generator and a method for generating a digital pulse width are provided. The method for generating a digital pulse width includes the following. Generating a first period according to first set of bits of pulse data. The first period includes an interval. First phase signals are set to a first logic value in the interval and are generated according to first phase clock signals after an end of the interval. Second phase signals are set to the first logic value in the first period and are generated according to second phase clock signals after an end of the first period. Selecting a first signal from the first phase signals and the second phase signals according to second set of bits of the pulse data as a pulse width signal.