The invention discloses an energy storage system charge-discharge control method based on two-degree-of-freedom PID. The method comprises the steps of: determining whether the current state of an energy storage system is in a charge or discharge state or not, if yes, acquiring a target value of a charging current or a discharging current of the energy storage system according to electrical parameters related to the electrical system, acquiring a charging current value or a discharging current value of the energy storage system in real time, processing the acquired charging current value or discharging current value by using a sliding filter algorithm to obtain a processed real-time charging current value or a processed real-time discharging current value, calculating a difference value between the acquired real-time charging current value or the real-time discharging current value and the acquired target value of the charging current or the discharging current of the energy storage system, and performing two-degree-of-freedom calculation according to the difference value to acquire the duty ratio of a switching element of the energy storage system. The energy storage system charge-discharge control method and system can solve the technical problem that the method cannot simultaneously achieve the optimal charge-discharge current response speed and the optimal anti-interferenceperformance in prior art.