Abstract: Based on the relationship between annual power generation and year-end energy storage, a multi-objective prediction model for the optimal year-end water level of carryover storage reservoir is developed, which gives a full consideration to maximizing the hydro energy and least output of the hydro plant at such a reservoir. The model was validated with the case of Longyangxia reservoir on the upper Yellow, and the essence in obtaining its optimal year-end level was revealed through analysis of the impacts of water inflow and year-start level on this optimal level. The operation results simulated by the model are further compared with the prototype operation case of this reservoir from 1990 to 2012. This shows that since 2006 it has run at a higher level than before 2006, which improves its own benefits and indicates that the multi-objective model is reasonable and feasible.