Dynamics of storage capacity of the Danjiangkou Reservoir have important significance to guarantee water diversion middle route project. Aiming at the problems of complexity in measurement and short-term fluctuation in capacity in Danjiangkou Reservoir,we chose remote sensing data of Landsat series and HJ-1A/B,and DEM data,constructing a new method for extraction of dynamic storage capacity,extracting the monthly dynamic information of reservoir capacity in 2000- 2016. We analyzed the factors that caused the dynamic change of storage capacity and its impacts on water diversion. The results showed that,in the past 17 years,the largest reservoir capacity of Danjiangkou was 19.216 billion m~3 and the minimum was 7.974 billion m~3,with an average of 11.204 billion m~3 . After the first phase of the middle route of south-to-north water transfer,the storage capacity of Danjiangkou Reservoir had been gradually increased. In terms of the monthly averages, the capacity from May to October increased gradually,from October through December showed fluctuate change,and decreased gradually from December to next May. The cyclical artificial storage and climate change were the driving forces for the changes of the storage capacity. The Danjiangkou Reservoir could meet the need for water transfer under the reasonable dispatching of the reservoir water.