The present study collected research-related data with the aim of investigating the impact of political risk on equity costs by emphasizing the moderating role of political relations. This research is of applied type and the data are of post-event observation type. The research method is descriptive-correlation in which the theoretical foundations and background of the research are collected through libraries, articles and the Internet and inductive reasoning is used as deductive reasoning and in rejecting or proving research hypotheses by using appropriate statistical methods. The statistical population determined in the present study includes companies that are members of the Tehran Stock Exchange for the period 1391 to 1397 and a systematic elimination method was used to select the sample companies. To test the hypotheses of this research and to determine the relationship between independent and dependent variables, econometric models have been used and since the conclusion is through testing the available data, the research falls into the group of positive theories. Data panel data and statistical estimation method is regression of fixed or random effects. The results showed that political relations have a negative and significant effect on the cost of equity. On the other hand, political risk does not have a significant effect on equity costs. The results also showed that political risk did not affect the relationship between equity costs and political relations.