The invention provides an energy storage system scheduling method based on peak clipping and valley filling. The energy storage system scheduling method based on peak clipping and valley filling comprises the following steps of (1) reading load output data, energy storage parameters and time-of-use electricity price data which are predicted in a future day; (2) calculating difference between the existing data and a standard and electric cost expenditure before optimizing; (3) solving power outputting of an energy storage system under different weighting functions; (4) calculating evaluation indexes after peak clipping and valley filling are carried out; (5) calculating expenses of peak clipping and valley filling; and (6) making a weight coefficient curve for peak clipping and valley filling evaluation indexes and the expenses. Objective functions are adjusted, and the problem that objective functions with different physical significances and different dimensions cannot be subjected to weighting summation is solved effectively. The running cost of the energy storage system is reduced. Capacity allocation of the energy storage system can be optimized further by an owner of the energy storage system. The energy storage system scheduling method based on peak clipping and valley filling has certain applicability and operability.