[Objective] The introduction of virtual synchronous control complicates the sub-synchronous oscillation between double-fed induction generator (DFIG) and line compensation devices. To address this issue, a sub-synchronous oscillation suppression strategy based on model predictive control (MPC) for a virtual synchronous DFIG grid-connected system is proposed. [Method] First, the second-order expressions of virtual inertia and damping were derived from the virtual synchronous generator (VSG) impedance model, and the impact of parameter variations on sub-synchronous oscillations in the grid-connected system was investigated from the perspective of impedance characteristics. Second, using a three-phase two-level voltage equation with switching functions, the prediction functions of active and reactive power output from the converter were derived. A direct power predictive inner-loop control based on MPC was established to achieve optimal control with minimum power fluctuation. Finally, the MPC_VSG control strategy was analyzed using the frequency sweep method. [Results] The proposed MPC_VSG control strategy was verified by hardware-in-loop experiment based on RT-LAB .The results demonstrated that, under different series compensation levels and wind speeds, the MPC_VSG control strategy can suppress sub-synchronous oscillations within 0.5 seconds, and exhibits strong robustness. [Conclusion] The MPC_VSG control strategy designed in this paper selects the optimal switching state by targeting minimal power fluctuations, achieving the subsynchronous oscillation effective suppression.