The PWM waveform generation device comprises a time-division multiplexing module, wherein the time-division multiplexing module is configured for receiving a first preprocessing signal and a second preprocessing signal output by two system clock sources, performing a first time-division processing on the first preprocessing signal to obtain a first time-division signal, and performing a second time-division processing on the second preprocessing signal to obtain a second time-division signal according to a preset strategy, performing multiplexing processing on the first time-division signal and the second time-division signal to obtain a PWM output signal, wherein an output frequency of the PWM output signal is a default standard clock frequency. The present invention has the advantages that the cycle length of one cycle of a PWM waveform depends on cycles of two preprocessing waveforms and the number of the cycles, such that the output waveform frequency may be calibrated to a desired frequency.