It is fearfully important to study power generation risk dispatching of hydropower stations under the condition of electricity marketing.Having reviewed the research state of mid-and long-term risk dispatching of hydropower station,this paper describes the uniform-different-contrary characteristics of flow,generation water and power price, and presents a model of mid-and long-term risk dispatching based on set-pair analysis.By using the method of first- order second order moment,probability risk-analysis gets the quantificational relation between benefit and risk.At the same time,sensitivity analysis (based on uncertain number i) provides the changing scope of generation income,which is caused by alterable risk genes.The case study shows feasibility and validity of the model.