Abstract: Chaotic and stochastic behavior have different character in essentiality, the describing methods for the two characters are not scone each other, and identification of chaotic and stochastic behavior of rainfall and streamllow tune series in the watershed is the most unfxutant basHnent for modeling and forecasting it.In the last decade, many hydrologists have ergaged in the study of the diagnosis of chaotic behavior and the chaotic prediction methods of rainfall and streamllow tune series.The reconstruction of the phase space and the diagnosis of chaotic behavior as well as the chaotic prediction methods of rainfall and streamflow time series are reviewed.The two luniting conditions, the problem of data size and data noise are also discussed in chaon theory application to rainfall and streamflow tune series.