To solve the problems of current quality decreasing and poor grid stability of virtual synchronous generator (VSG) under the condition containing background harmonic,a power grid voltage feedforward control strategy based on current loop for VSG is proposed. In order to eliminate the influence of grid voltage background harmonics on grid connected current,the voltage feedforward control function is derived according to the input current transfer function. The impedance model of VSG with and without feedforward control are established based on the harmonic linearization method. The influence on both the impedance characteristics at different frequency range and stability of grid connection are compared and analyzed. The results show that the introduction of the feedforward control is equivalent to parallel virtual impedance at the output of VSG,so the amplitude frequency curve of output impedance in high frequency band moves up,which can improve the grid connected current quality under non ideal grid conditions. At the same time,the phase frequency characteristics of medium and high frequency band are corrected from capacitive to inductive,which can eliminate the risk of harmonic oscillation under grid connected conditions,and improve the stability of interactive system. Finally,a hardware in the loop experimental platform is built to verify the correctness of the control strategy model and related analysis.