To make the commander recognize the complicated electromagnetic environment and make correct decisionthe complexity evaluation of battlefield electromagnetic environment was studied.The common complexity evaluation methods was summarized at first.Thenan evaluation method based on value of a Game was proposed from the perspective of operational application.A model of evaluation was constructed and the solution under the optimal mixed strategy was given.The calculation of the scenario showed thatthis method can evaluate the degree of complexity while the both sides have multiple optional operation modes and make the optimized combat operation selectionthus can improve the decisionmaking and training effect.