In the research history of ecology civilization or national defense from the founding of the People’s Republic of China，“ecological national defense” has not yet been recognized as a well-accepted term. However，it doesn’t mean that the proposal of ecological national defense with Chinese socialist characteristics is short of history accumulation. From the author’s perspective，the theory content of ecological national defense rooted deeply in the theory of the ecological civilization with Chinese socialist characteristics. The practice path of the ecological defense in the new situation originated from and in the line with the environment protection and ecology construction by the military ever since the beginning of the reform and open，especially the new era and new time.