Abstract: This paper firstly analyzes and discusses the basic characteristics of the fractional reactance element,and builds a simulation module of the fractional reactance element on the Matlab/Simscape platform to realize the device-level simulation of the fractional-order photovoltaic inverter system. Secondly,the fractional-order high-frequency mathematical model of the three-phase photovoltaic grid-connected inverter is established,the decoupling control structure of the fractional-order current inner loop is deduced,and a fractional-order controller is introduced to establish a fractional-order photovoltaic grid-connected double closed-loop control system. The simulation results show that the built fractional reactance element simulation module can accurately simulate the external characteristics of the fractional reactance element in the selected frequency range,the fractional-order photovoltaic three-phase inverter has better dynamic and static characteristics,and the fractional-order photovoltaic double closed-loop control effect is obviously better than integer-order double closed-loop control.