Tax is one of important accounts in financial statement of firms. Tax avoidance is using of law for decreasing tax that financial and nonfinancial variables have effect on it. The purpose of this research is The Survey of relationship of type of shareholders (institutional and firm investors) and corporate tax avoidance and The Ratio of ‎cash flow Listed Companies in Tehran Stock Exchange. The research from the viewpoint of purpose is practical and from the viewpoint of execution method is descriptive-correlation. For this research 3 hypotheses is compiled. To conduct this research, we use regression models via Eviews 8 and spss 21 statistical software. This subject surveyed in Tehran Stock Exchange listed companies 134 since 2017-2023. The findings show that there is significant relationship among type of shareholders (institutional and firm investors) and corporate tax avoidance and The Ratio of ‎cash flow Listed Companies in Tehran Stock Exchange. Tax avoidance is the use of laws to reduce taxes that are affected by financial and non-financial variables. This research is to improve the tax compliance procedure of valuable companies.