Water-supply enterprise consumes much of electric energy in the city, and the quantity it consumes mainly depends on the pumps of pumping stations. So it is important to optimize operation of water-supply pumping stations, for safety water supply and saving energy. This paper presents an optimal scheduling model of water-supply pumping stations based on approximation of exponent curve. Corresponding to the model, solutions based on genetic algorithm are introduced. The simulation resuls illustrate its validity.