The objective of this paper is to present the achievements and important issues in the apphcation of chaos theory in hydrology, and to disseminate the potential for future improvements. This paper reviewed the application of chaotic identification, prediction, parameters for phase space reconstruction, noise processing and data size in hydrology. This paper also pointed out that chaotic approach should be compared and combined with other theories and the research of multivariate prediction and reconstruction of system dynamical equations may reveal the evolution and mechanism of chaotic hydrology.