Abstract: Compared with traditional two-level inverters, multi-level inverters have been widely used in the medium and high voltage fields due to their more output levels, lower switching losses, lower voltage stress, and better output voltage waveforms. In this paper, a novel three-phase quasi-four-level inverter topology and its SVPWM algorithm were proposed to address the problems of high cost, large size, complex modulation algorithm and difficulty in matching the same type of devices. The proposed inverter topology not only eliminates the need for clamping diodes or fly-through capacitors, but also simplifies the structure and saves costs. MATLAB simulation and experimental results show that under the maximum switching frequency of 10kHz, the THD of the output voltage can be controlled 0.78% and 4.904%, respectively, which is lower than the output harmonic content and the switching frequency of the traditional three-level inverter, and the conversion efficiency is improved by nearly 2%.