Single stage Z-source three-level neutral point clamped (NPC) inverter combines voltage-boost and inversion functions, and it has the advantages of simple structure and high efficiency. A constant power grid-connected control method for Z-source NPC three-level inverter based on space vector pulse width modulation (SVPWM) was proposed. First, the structure and working principle of Z-source three-level NPC inverter was analyzed. Then, the constant power control strategy was introduced to Z-source three-level NPC inverter grid-connected system. Finally, simulation model of the system was built in MATLAB/Simulink software. The simulation results showed that Z-source NPC three-level inverter could boost the step-up ratio, this control method could make the output active and reactive power of the grid inverter track the set value effectively, and grid current harmonic content components were low.