Abstract: Based on the analysis of annual maximum flows between 1951 and 2001 in Tongguan,Huayuankou and Lanzhou,a new model for the multi step prediction is proposed in the paper.The model is well available for continuous multi step pre diction and anomalous extreme values.The example,applying the model to the multi step prediction of independent sample during 1995-2001,results show that the tendency of variation for every year can be predicted skillfully by the model.The variation for the flow during 2002-2005 is also predicted.