Abstract: The quasi-Z-source H-bridge grid-connected inverter（GCI）is well known as its no shoot-through problem and high efficiency of DC voltage,but the common-mode leakage current exists in the power frequency cycle. To solve the problems of quasi-Z-source Hbridge GCI,a new Z-Source photovoltaic grid-connected inverter（ZPGCI）with coupled cnductor coil topology is proposed. Also,a unipolar sinusoidal pulse width modulation（USPWM） strategy that can make the common-mode voltage constant is presented.Secondly,operating modes,common-mode leakage current and direct operating mode analysis shows that ZPGCI not only has the advantages of no shoot-through problem and high reliability,but also can eliminate the high-frequency common-mode leakage current of quasi-Z-source H-bridge GCI. At last,the correctness of the novel ZPGCI topology and theoretical analysis are verified by the comparison experiment of traditional quasi-Z-source H-bridge GCI and new ZPGCI circuit.