In view of the conventional droop control method of inverter existing voltage and frequency offset in the steady state, cannot fully meet the requirements of the grid operation, a new control strategy of inverters called virtual synchronous generator(VSG) is adopted. A virtual synchronous generator model is established, focusing on the design of the power frequency controller and excitation controller based on synchronous generator control theory. An inverter grid-connected system which uses a large capacity steam turbine generator to simulate grid is built. The role of the rotational inertia and the grid-connected regulation characteristics of virtual synchronous generator are verified through Matlab / Simulink simulation. The results show that, the inverter based on virtual synchronous generator control strategy is approximately equivalent to a synchronous generator in external characteristics, has advantages in modulating frequency and voltage and is conductive to grid operation.