Abstract: Economic operation is an essential approach to improve economic benefits of a hydropower station. However, previous studies in China and abroad tended to focus on theoretical optimal solutions that had insufficient consideration of the risks of abandoning water and hence suffered certain deviation from reality. Aiming at this issue, this paper presents an economic operation model that takes constraints of controlling the water level amplitudes in different water level inter-regions and achieves an optimal load allocation by considering risks and unit commitment and coordinating the operations of the upper and lower hydropower stations. Application to the Wuxi cascade hydropower stations shows that this new model can achieve an optimal combination of generator units that effectively reduces the volume of surplus water and controls the risks, and thus it would provide a rather satisfactory guide for optimal unit commitment of the cascade stations.