A digital pulse width modulation controller includes a pulse width modulation controller, a selection unit having at least one selector, a comparison unit having at least one comparator, and a signal conversion unit having at least one digital-to-analog converter. The digital-to-analog converter generates a reference current and/or voltage. The comparator receives the reference current and/or voltage, and performs a comparison operation to generate a comparison signal based on a feedback signal. The selector selects one selection signal to input into the pulse width modulation controller, which receives other parameters set by a user or the system at the same time so as to control characteristics of the digital pulse width modulation signals, thereby improving the electric properties of a loading circuit.