The certainty and randommess method have a certain dificiencies in analyzing the course of flood.Accoreling to the thaotic characteristics existed in nature,based on the chaotic characteristics caused by non-linear and certarnty system,the paper analyzed the chaotic characteristies of flood system,established the volterra stlf-adaplive prediction model based on chaotic theory and used the phase-space restructure to get training samples.The model was used in forecast of the largest flood in 2004 at shitan hy...