Abstract: In order to output stably the high DC voltage required by the inverter bus stably,the photovoltaic system needs a high stepup DC-DC converter to improve the voltage level of photovoltaic modules. Therefore,a quasi-Z source soft switching high step-up DCDC converter is designed in this paper. The converter can be used in the photovoltaic system. Based on the quasi-Z source framework,active switches are used to replace diodes,and coupled inductors and switched capacitor modules are embedded in the quasi-Z source framework to achieve the soft switching operation,high voltage gain and high efficiency. This paper introduces the working principle of the converter,analyzes the performance under steady state,compares its performance other converter,and verifies the correctness of the analysis with the modeling simulation and prototype experiment.