The social dynamics of cities have long been dependent on their spaces and places. On the one hand, human interactions, and relationships are formed by the city form and on the other hand, the body recovers its identity from existing social life. The more a city can communicate with its citizens through physical features, the more it will affect their social identity. Thus, the city form can have a considerable effect on the relationships and social capital among humans. Karaj city is the second immigrant city because of being close to Tehran Capital of Iran. Nowadays, the slumming phenomenon in Karaj has become a fundamental problem that the physical distinctions of the slum districts seem to have led to a change in the social capacities of the district. Based on the survey and using processed data extracted from the questionnaire in a quantitative model through SPSS software, physical characteristics and architectural spaces of Zurabad neighborhood of Karaj contribute to the decline in social capital of the people in this neighborhood to 79%, resulting from reducing people's trust in the neighborhood up to 84%, its people’s security up to 85%, its people’s sense of belonging up to 72% and in its people’s participation up to 75%. These results indicate the urgent need for immediate attention to the body and context of this region that shapes each individual's social and individual identity over time.