Based on the precipitation and flow curve data during 1959—1997,the relationship between the precipitation and the flow curve in the upper reaches of the Huanghe river was analysed by using of the mathematical statistic forecasting methods of EOF,REOF,power spectrum,and trend analysis etc.The variation trend of precipitation over the upper reaches of the Huanghe river was also studied.The optimum assesment model of the flow curve prediction was established by means of the stepwise regression and optimum subset regression.