This paper presents a seamless switching control strategy based on virtual synchronous generator (VSG) control and voltage and current internal model control (IMC) for voltage distortion and impulse current in the switching process betweeen grid-connected and off-grid of the Inverter. Firstly, the control structure and mathematical model of the inverter are established.Secondly, the control structure with voltage and current double-loop based on IMC is designed and the parameters of internal model controller are adjusted. Thirdly, the pre-synchronization control method based on amplitude and phase of the voltage is adopted to enable the inverter to switch smoothly between the two models, and the transient voltage and current of switching is stable, which realizes the smooth transition. Finally, the effectiveness of the proposed control strategy is verified by the Matlab/Simulink simulation.