A new control strategy, virtual synchronous generator (VSG), can improve the friendliness of the distributed generator (DG) to the power grid by imitating the output characteristics of the traditional synchronous generator. However, the traditional VSG cannot suppress the fault current or provide reactive power support in the case of power grid failure. To solve this problem, the behavior of VSG in the process of symmetrical voltage sag is analyzed based on an established VSG model. After that, a control strategy, which can avoid overcurrent and transient current impact during the voltage sag fault, for VSG with maximum reactive power compensation is proposed. The control principles of the current limiting control method and setting principles of the specific parameters are also given. Finally, the correctness and feasibility of the proposed control strategy are verified by simulation.