The invention provides an energy storage capacity configuration method and system of an electric vehicle charging station. The real-time active power needing to be stored every day is calculated basedon a pre-acquired charging station daily real-time charging active power curve and a pre-acquired photovoltaic system daily power generation active power curve; a day is divided into multiple time periods based on the charging station daily real-time charging active power curve, and corresponding electricity prices are set; the electricity prices corresponding to the time periods are compared with the on-grid price, the configuration capacity of stored energy is obtained based on the real-time active power needing to be stored every day, and therefore the total revenue of the photovoltaic integrated charging station in the project whole life cycle is maximal under the condition that the charging pile power, the vehicle charging requirement and photovoltaic system mounting are unchanged.