Abstract: In this paper, the history of the hydrologic frequency analysis and research is reviewed, the commonly encountered problems, such as the type of frequency curves, the empirical frequency formulas, estimation of statistical parameters and application of special data, are described. The summary of main accomplishments for the frequency analysis in recent 50 years is emphasized, and the analysis idea, the exploring study, the practical application and the practical experience are dissected. It is considered that, now there are a set of hydrologic frequency methods having Chinese specialty are developed to provide the scientific grounds for engineering needs and to act as contribution for development of the hydrologic science.