The utilization rate of DC voltage of traditional neutral-point-clamped (NPC) five level inverters without voltage-boost capability is low.The dead zone is needed in order to avoid shoot-through state,which causes the decline in the system security.With a unique X-shaped LC network,a Z-source inverter can gain boost ability and improve the reliability utilizing the shoot-through state. The topologic of NPC five level Z source inverter with two Z-source networks was proposed.Its shoot-through state was analyzed and the rationality of this topologic was illustrated. Based on phase disposition (PD) pulse width modulation (PWM) algorithm of conventional NPC five level inverter,a practicable PD PWM algorithm was designed for five level Z source inverter.The simulation results demonstrate the rationality of this modulation method and the advantage of NPC five level Z source inverter in improving the utilization rate of DC voltage.