The application of discontinuous pulse width modulation (DPWM) in high-power inverters can effectively improve the equivalent switching frequency of the inverter and improve the control performance of the system. In this paper, the DPWM3 algorithm of NPC type three-level inverter is researched in detail from the judgment of the sector where the reference vector is located, the calculation of the action time of the space vector, and the selection of the switching sequence. Finally, simulation and experimental results verify the rationality of the proposed algorithm. It provides a certain reference value for the research of NPC three-level inverter discontinuous pulse width modulation algorithm.