A novel combined control strategy for both virtual synchronous generator and Active Power Filter (APF) is proposed. The relationship between the reference current of virtual synchronous generator and the harmonic voltage of power network is analyzed, the necessity of extracting the fundamental voltage for the reference current generation in the combined control strategy is demonstrated, and a virtual generator reference current generation algorithm based on multiple second-order generalized integrator structure is given. The shock current caused by the application of virtual synchronous generator in the multi-function grid-connected inverter is analyzed, and the improvement method is put forward. System simulation is carried out on Matlab/Simulink and simulation results verify the validity of the proposed control strategy. This work is supported by Scientific and Technological Breakthrough Plan of Henan Province (No. 172102310757 and No. 182102210333).