In a distributed grid-connected power as the background, in order to improve the booster of inverter capacity, for the purpose of exploring new inverter topology, this paper proposed an improved tapped inductor Z source inverter, which is the basis for the quasi Z source inverter in the improvement of the tapped inductor. Compared with the tapped inductor Z source inverter, the improved topology using symmetric tapped inductor structure, adding a tapped inductor, a capacitor, two diodes. The ability of the proposed boost inverter has higher, and we can regulate the boost ratio using the tap position. This impedance network is symmetry, reducing the device voltage stress, enhancing the reliability of the system. This paper analyzed the steady state decoupling circuit, boost capacity comparison of several different topologies and to explore the modulation strategy. design and accomplishment of experiment were discussed and experimental results were provide to verify the real performance of the proposed inverter. This indicates that the inverter has good performance, meet the requirements of distributed power grid power of inverter.