The charge and discharge control apparatus divides a stored electricity amount of a storage battery into a backup electricity amount and a plurality of predetermined discharge amount corresponding to a plurality of dispatching time points. Each of the dispatching time points corresponds to a dispatching period and a predetermined discharge power. The charge and discharge control apparatus receives a load parameter of an electric loop at each dispatching time point. Each load parameter carries a load power of the electric loop. The charge and discharge control apparatus performs the following operations at each dispatching time point: (i) deciding a real discharge power that the storage battery provides to the electric loop according to a dispatching threshold and the load power corresponding to the dispatching time point and (ii) updating the backup electricity amount according to the real discharge power and the predetermined discharge amount.