This research with title" study of relationship between youth, s family social capital and their religiousness in Tehran city". To pay of study relationship of youth , s family social capital with kind and measure their religiousness. For do this research, choiced 358 person of youths 18 untill 29 years from area, s 3 10, and 16 in Tehran. Instage of analysis datas' used from methods correlation tests and regression. The results of this study show that there are relation significance between youth, s family social capital with kind and measure their religiousness .also between indicators subjective distance and objective distance family social capital is relation significance. The results of regression show that from among indicators objective distance' parents life most share in anticipation measure their religiousness and also from among indicators subjective distance' cooperate most share in anticipation measure their religiousness. When control family social capital 'saw that in families with high social capital there are high correlation between measure religiousness, s parents and childrens until familes with low social capital.