Abstract: Offshore wind farms must have low voltage ride-through (LVRT) capability to avoid wind turbine disconnection in case of failure. However, the impact of LVRT strategy on the stability of grid-connected systems after large disturbances is unknown. Because of this, the equivalent model of PMSGs interfaced with the AC power grid is established. Meanwhile, the mechanism and characteristics of different types of oscillation caused by LVRT under large disturbance when the connection is weak are analyzed in this paper. The details are as follows: Firstly, the electromagnetic transient model of an offshore direct-driven wind farm with LVRT is built. Secondly, the impedance characteristics of the system are analyzed, which shows that the system is at risk of subsynchronous oscillation. After the positive damping system with a weak connection is subject to large disturbance, a subsynchronous frequency band oscillation will be formed by LVRT participation. Thirdly, the relationship between the oscillation and different control principles of LVRT is explored, which shows that strategy 1 or 2 of the stage 2-1 in a reactive link of LVRT for a system with positive damping after a large disturbance can participate in the formation of switched oscillation caused by excessive compensation current, and the phenomenon that intermittent saturation of limit exists in the oscillations corresponding to both control strategies. Finally, the influence of LVRT control parameters or strategies on the oscillation characteristics is analyzed.