Passive defense is one of the contemporary issues, which has been considered in urban plans. Nowadays, this issue is included in urban master plans via setting specific regulations on location of land uses and empowering of buildings which can be used for all cities(not only the case study). This research contributes to decrease in possible damages from military attacks in cities by introducing a new method, analyzing city and it`s effective elements on passive defense. Birjand is one of the border line cities of Iran which due to be the center of Southern Khorasan province and locating of managerial and strategic centers, has a special condition. To identify the vulnerable elements of this city from passive defense point of views, the Delphi method were used regards to the previous studies had been done on this issue? Base on this, a twenty-item list containing the vulnerable elements prepared and valued by Analytic Hierarchy Process (AHP). Then the vulnerability layer produced with the interpolation density analysis using GIS software. In addition to the vulnerable elements, the effective urban indexes on this issue such as population densities and size of plots have been surveyed in order to prepare the vulnerable layer of the city. After this, the produces layers mixed with each other and make the final vulnerable zoning of Birjand with passive defense approach. At the end, based on the analysis conducted about each urban element, the mitigating solutions and recommendations proposed in order to decrease the level of damages from military attacks.