Abstract: The grid-connected photovoltaic (PV) systems generally operate in the maximum power mode, where they are unable to fully respond to the adjustment requirements of the power grid. Therefore, research on power reserve control (PRC) for PV systems is needed. The maximum power point estimation (MPPE)-based PRC applies the equivalent model of a PV module to realize power reserve in the PV system, where the MPPE is conducted based on curve fitting. However, with the aging of PV modules, the error in MPPE increases, potentially impacting the stability and security of the system. A PRC method for PV systems that considers the correction of model parameters in MPPE as PV modules age is proposed in this paper. Firstly, a correction method for model parameters in MPPE is proposed based on the sparrow search algorithm. Then, considering the aging characteristics of PV modules and the evolution trend of MPPE error, an improved assessment criterion for the correction of MPPE model and the tuning principle of correction periods are proposed and finally applied to the MPPE-PRC method. Simulation results show that the proposed method can automatically correct the model parameters in MPPE as PV modules age. It can significantly improve the MPPE accuracy and enhance the reliability of PRC in practical applications.