Abstract: This paper puts forward the design of the Flood Control Decision Case Management System (FCDCMS) based on the analysis of the characteristic of flood control decision making. Taking the Yangtze River Flood Control Decision Support System (YRFCDSS) for an example, the paper describes some decision case management methods, such as creating new case, deleting old case, selecting the case, selecting the model in the case, setting the model parameter, running the model, displaying the result of model, getting the case description, comparing the result of many cases, and so on. Meanwhile, the technique of development is expounded in the paper.