The invention relates to a method for detecting inductance in impedance of power grids with three-phase photovoltaic grid-connected inverters. The method includes allowing the three-phase photovoltaicgrid-connected inverters to work at first working points, and measuring output voltage vectors and output current vectors of the three-phase photovoltaic grid-connected inverters when the three-phasephotovoltaic grid-connected inverters work at the first working points; allowing the three-phase photovoltaic grid-connected inverters to work at second working points, and measuring output voltage vectors and output current vectors of the three-phase photovoltaic grid-connected inverters when the three-phase photovoltaic grid-connected inverters work at the second working points; converting theoutput voltage vectors and the output current vectors of the three-phase photovoltaic grid-connected inverters when the three-phase photovoltaic grid-connected inverters work at the first working points and the output voltage vectors and the output current vectors of the three-phase photovoltaic grid-connected inverters when the three-phase photovoltaic grid-connected inverters work at the secondworking points into dq rotating coordinate systems and carrying out computation according to various values in the dq rotating coordinate systems to obtain inductance portions in the impedance of voltages of the power grids. Given currents of reactive power of the three-phase photovoltaic grid-connected inverters when the three-phase photovoltaic grid-connected inverters work at the first workingpoints and the second working points are different from one another. The method is free of influence on the performance of the inverters, and has the advantages of simplicity in computation, convenience in control and the like.