With the integration of large-scale new energy into the power grid, battery energy storage can effectively suppress the frequency stability problem caused by the fluctuation of new energy power in automatic generation control with its fast and accurate characteristics. To this end, a strategy of battery energy storage assisting secondary frequency regulation based on model predictive control is proposed in this paper. The control strategy divides the area control error signal into different intervals, taking into account the grid’s frequency regulation demand and the battery energy storage system’s state of charge recovery requirement. The output target and the output depth of the battery energy storage are determined based on the model prediction control in each interval. Taking the two-zone interconnected power grid frequency regulation model as an example, the results show that compared with other control strategy, the control strategy proposed in this paper not only has a good suppression effect on frequency deviation and area control error under the premise of safe work, but also ensures the balance between frequency control quality and self-charge state.