Abstract: In order to solve the problem of reducing the system equivalent damping and inertia caused by the increase of distributed new energy penetration, some scholars put forward the virtual synchronous generator (VSG) control strategy. The VSG mostly adopts the positive and negative sequence compound control based on the d-q axis under the two-phase rotating coordinate system, so as to suppress the negative sequence component in the grid current when the grid voltage drops asymmetrically. However, the delay of positive and negative sequence separation worsens the transition process of VSG output current when the grid voltage sag fault occurrs or recovers, resulting in an increased risk of the VSG overcurrent. Aiming at this problem, the article firstly analyzes the characteristic of grid voltage equivalent amplitude waveforms when the grid voltage drops symmetrically and asymmetrically, and a low voltage ride-through strategy of the VSG that may automatically identify the fault types to achieve the adaptive positive and negative sequence compound control is proposed. The method does not only suppress the negative sequence component in the output current under asymmetric faults, but also reduce the delay effect of positive and negative sequence separation and the possibility of the VSG transient overcurrent, making the transition process of the VSG output current smoother when the fault occurrs or recovers. Finally, simulation system is built to verify the feasibility of the proposed method.