Abstract: The calculation of storage and flood control capacity of river network is of great significance to the scientific storage and rational regulation of river water resources. This paper takes the regional river network of Huantai County as the research object,and constructs a structure decomposition model of river water resources. Based on the natural attributes of different water quantities,the method divides the whole volume of river water into four parts:namely environment water portion（EWP）,safety water portion（SWP）,risk water portion（RWP）and disaster water portion（DWP）with the characteristic water level of ecological water level,waterlogging level,flood control design water level and dike top elevation. In order to maximize the natural“storage tank”function of river network and explore the storage and flood control capacity of regional river network under different scenarios,combined with the river water division model of Huantai County,this paper selects four river network storage and flood control capacity indexes（storage and flood control capacity,regulation storage capacity,storage and flood control capacity per unit area and regulation storage capacity per unit area）to calculate the storage and flood control capacity under ecological operation,resource operation and flood control operation of river network in Huantai County. The result shows that the calculation method of storage and flood control capacity of river network based on river water division can fully reflect the interval attribute of storage and flood control capacity,and lay a good foundation for the selection and implementation of different regulation schemes in Huantai County.