The invention discloses a method for evaluating states of excitation systems of water pumping energy storage units. The method includes determining numerical values of various subject factor indexes of the excitation systems of the water pumping energy storage units according to operation parameters of the excitation systems of the water pumping energy storage units; constructing subject factor importance degree matrixes according to importance degrees of the various subject factor indexes and acquiring weights of the various subject factor indexes according to the subject factor importance degree matrixes; acquiring evaluation values of the excitation systems of the water pumping energy storage units according to the numerical values of the various subject factor indexes and the weights of the various subject factor indexes. The subject factor indexes comprise voltage stability factors, dynamic stability factors, typical working condition factors and critical temperature factors. Themethod has the advantages that complete comprehensive state evaluating models are built for the excitation systems of the water pumping energy storage units, accordingly, the states of the excitationsystems of the water pumping energy storage units can be scientifically and objectively evaluated by the aid of the method, and the method has guiding significance in the aspects from planned maintenance to state maintenance on the water pumping energy storage units.