Abstract: To solve the issues of reduction of the system frequency stability caused by large-scale wind power integrations,the shortterm frequency support can be obtained for the wind turbine generators by using virtual inertia control. However,when performing virtual inertia control,the slow rotor speed convergence results in the unnecessary waste of the rotor kinetic energy. The sudden change of active power during the rotor speed recovery stage is prone to cause the second frequency drop（SFD）. To this end,this paper proposes an improved virtual inertia control strategy of wind turbine generators based on torque limit. The proposed strategy can preserve the frequency nadir with the less released rotor energy;when the system frequency reaches to the quasi-steady state,the rotor speed recovery is started with time-varying power function so as to realize the rapid speed recovery while alleviating the SFD. The proposed virtual inertial control strategy is verified based on an electric power system model embed with a doubly-fed induction generator-based wind power plant using on EMTP-RV.