Abstract: Due to the influence of parasitic parameters of power switching devices, not only the output ripple voltage and inductance current ripple of interleaved control three-level buck converter are distorted, but also there is a large error between the ripple voltage and the ripple voltage ignoring parasitic parameters. In this paper, the output ripple voltage distortion mechanism of interleaved three-level buck converter is deeply analyzed, and the mathematical models of inductor current ripple and output ripple voltage considering the parasitic parameters of power switching devices are established. The experimental results show that the parasitic parameters of power switching devices are the main reason for the distortion of output ripple voltage waveform and large error with the ideal model. The experimental results verify the correctness of the theoretical analysis, and the conclusions can provide theoretical guidance for the converter parameter design of three-level buck converter.