The subject of civil defense (passive defense) with its general and broad concept is a set of non-armed measures that lead to increased deterrence, reduced vulnerability, continuity of essential activities, enhancement of national sustainability, and facilitation of crisis management against enemy threats and military actions (preserving vital infrastructure against aggression without armed and direct conflict), which has a long history in human history. The study and examination of the history of casualties, damages, injuries, losses, and damages resulting from wars indicate the fact that by knowing and observing the principles, measures, and strategy of civil defense as a complement to active defense, one can, by spending less time and cost, while making war costly for the enemy, prevent huge damages and losses to destiny-making centers. This article, with the aim of investigating the role of civil defense principles in enhancing country security in dealing with threats, and by analyzing opportunities, threats, strengths, and weaknesses, seeks to answer the question of what role the observance of civil defense principles will play in enhancing the country's security against external threats? To answer this question, the researcher tries, using a descriptive-analytical method and collecting library and documentary information and valuable experiences of past wars, to minimize casualties and damages to centers of gravity through passive defense measures and the use of various ruses, increase the cost of war for the enemy, and ultimately, by raising the threshold of resistance, preserve national security, national assets, and the country's independence.