Abstract: As to the interacting influences among control systems caused by multiple inverters connected to weak power grid, which is studied by using the SVD method. The equivalent model of weak-structured power system with multiple grid-connected inverters is established, SVD is used to quantitatively analyze the interaction influences among control systems of multiple inverters, and varying characteristics of interaction influence angle θ varying with the number of grid-connected inverters, control parameters and equivalent impedance of power grid is given with the premise of ensuring the stability of power system. In the end, the power gird model with multiple grid-connected inverters is built on Simulink simulation platform to verify the correctness of analysis results. At the same time, general rules that the interaction influences among control systems for multiple grid-connected inverters on the containing rate for certain harmonics are accurately descripted.