Abstract: With the continuous increase of photovoltaic（PV） power in China, large-scale photovoltaic grid connection introduces a lot of power electronic devices, and there is a risk of sub-synchronous oscillation（SSO） in photovoltaic grid-connected systems. In order to solve the potential sub-synchronous oscillation problem of photovoltaic grid-connected system, a model predictive control method based SSO suppression strategy for PV grid-connected system is proposed. Firstly, establish a small signal analysis model for PV gridconnected system considering the inverter control delay, and use the participation factor analysis method to select model with good observability and controllability to predict control signal. Secondly, establish appropriate objective function and constraints, and solve the optimal input sequence of the system through model predictive controller to make the system output reach the expected value, thereby suppressing the system oscillation. Finally, the effectiveness and robustness of the SSO suppression strategy are verified through simulation.