Abstract: Historic architecture and urbanization in Iran encompass the principles which have manifested in the traditions. Traditional urbanization and architecture has enjoyed a special place with an emphasis on sustainable features and creativity. Yet, the investigations in recent decades specify that architecture has sustained far from the reality due to uncontrolled growth of Yazd and exposure with various factors, whereby the challenges have appeared in traditional architecture and modern urbanization. The challenges include unbalanced expansion of cities and spatial discontinuity of city, poor urban density, problems of urban transport and increasing costs. In other words, in current age, some changes have been brought about in urbanization and architectural patterns due to exposure with various factors. Nowadays, cities have kept developing by a rapid speed, under which significance of public spaces has increased. The present research seeks to investigate fuzzy logic in passive defense in this context and propose a special approach for a more favorable design and development of it.