National security also includes the security of land, people and politics, which are not only related but also different. In fact, all kinds of national security issues are the concrete embodiment of these three original national security in different time and space and different fields, which is the secondary category of national security and does not belong to the original level of national security. For example, homeland security is affected by military security, scientific and technological security and other relevant independent variables, political security is related to military security, cultural security and other variables, and people's security is related to resource security, nuclear security, ecological security and other variables. Therefore, clarifying the connotation, denotation and internal relationship of national security, clarifying the internal structure and situation of national security system, and grasping the core national security issues are very important for improving national security theory and ensuring national security. The author believes that land, people and politics are the three original levels of national security, political power is the "umbrella" of national security and people's security, political security is the foundation of national security, without political security, there is no way to talk about land and people's security. Political security should be placed in the priority sequence of the national security strategy. Great changes have taken place in the international situation after the Cold War, and the possibility of foreign military forces directly overthrowing the regime has been greatly reduced. in this case, the role of political identity in the construction of political security has become increasingly prominent. Therefore, political identity must be taken into account in order to achieve national security. Cultivating political identity and ensuring political security has become the key path to achieve national security.