Water transfer compensation characteristics include the two aspects of hydrological compensation and reservoir capacity compensation. Taking the 2 important water supply reservoirs of Biliuhe and Yingnahe as an example, the Copula function was applied to analyze the wetnessdryness encountering probability of the annual natural inflow of the reservoirs, the inflow in flood season and dry season. The statistical method was used to analyze the wetness-dryness encountering of consecutive dry years between the reservoirs. The joint water supply dispatching optimization model with external water resources was established to simulate the water supply and discharged water of the reservoirs in planned year. With the simulation result of the relationship between the discharged water over the years, the capacity compensation characteristics of the reservoirs was analyzed.