The purpose of this study is to search for the newly emerging concepts and contents of comprehensive security and suggest the kinds of national crisis according to the change of national security environments. For achieving the goal, this paper reviewed some concepts of comprehensive security, human security, cooperative security or common security, and transnational threats. And the researcher has tried to find the changes of national security environments, for example, traditional military security environment change, emergence of economic security threat, importance of environmental security, significance of human security, etc. So, in this paper, national security from the perspective of comprehensive security can be defined as a state that protect a people, territory, sovereignty, and critical infrastructure from military and non-military crisis which threaten the sustainable development of a nation. In this context, national crisis can be classified as people living crisis, disaster crisis(natural and man-made disaster), traditional military crisis which threaten territory and sovereignty crisis, critical infrastructure crisis, etc.