A simplified multilevel DC converter circuit structure comprises a dual input DC power supply, a power control module and an AC side low-pass filter, wherein each of the dual input DC power supply supplies half of the rated DC voltage to the power control module, and the power control module is composed of six power switches, and different switching combinations of each power switch are controlled to convert a DC voltage to an output of an AC voltage, and two of the power switches of the power control module perform a low-frequency switching twice every cycle of the output voltage, and the withstand voltage is equal to the input voltage, and the remaining power switches perform the switching by a high frequency, and the withstand voltage is only half of the input voltage, such that a multilevel voltage can be outputted, and a low harmonic AC waveform can be outputted from the AC side low-pass filter.