Objective: Giving an explanation for falling of social capital in Post - revolutionary Iran is the main aim of this article. Method: There are two hypotheses: fist, are social capital during this period has felled. Second, the weak governance is the main reason for it. Before going to test these hypothesizes, we have tried to show that there is, generally, a multidimensional causal relation among the economic, political and social factors, in first and second parts of article. At the same time, this point has been argued that one of these factors could be considered as the start point of multidimensional relation, depending on special historical situation of a society. Then, in third to fifth parts of article the hypotheses have been tested, using the data issued by international organizations including World Bank, UNDP and International Transparency Organization as well as the published data by different field studies. Finding and Result: First, social capital during the years after revolution has been felled second, the main reason for this falling is related to weak governance during these years.