Developing Security as one the most fundamental human needs, in addition to primary needs (physiological), can underlie other needs. Reducing the Human damages and decreasing the vulnerability of the critical facilities and equipment of the country in enemy hostile and malicious attacks with keeping support activities in crisis of war, are among essential acts in the planning of human settlements that are generally known as Passive Defense. In this paper, Bandar-e Anzali (Anzali Port), as a coastal city with high economic performance, was selected as a case to study and its gravity centers were reviewed and evaluated by implementing an analytical method so called proposed prioritization gravity centers matrix and finally defensive strategies for the city are proposed using SWOT matrix. Development and creating safe spaces in important and primary centers, creating several major centers instead of single critical centers, reducing the risk of hazardous land uses and distribution of main centers in the city, are among these strategies.