The relationships between human and security, and space and activity is among the essential elements in formulating spatial planning projects which leads to consolidation, development, sustainability and security. Defending a territory, either on national scale or regional level, besides its political and geographical content, includes defending the existing establishments as well. If a country's defense plan doesn't consider security of human and activities, instability will be the main functional and physical threat to the space. The research is intended to study the security-building factors of passive defense in spatial planning. We try to answer the question that which one of the involved variables, from the viewpoints of the field experts, plays the prominent part in the issue? Descriptive-analytic approach was used in the paper. In order to come down on research topic, quantitative (assessment using SPSS) and qualitative (interview) approaches were utilized besides librarian studies. Statistic universe of the research included 275 people associated with passive defense organizations as well as the technicians and university experts in Tehran, Iran. The results of the paper indicated that suitable locating, consolidation, sharing experiences of the developed countries on the field and using natural factors are among the most important security-building factors of passive defense in spatial planning.