This research examines the effect of the Capital Buffer, on banks as a regulatory and controlling factor on the relationship between liquidity risk and banks' risk aversion. In this study, eight banks were surveyed for the period of 2011-2014. In order to measure the Capital Buffer criterion, the legal deposit rates of central bank of the Islamic Republic of Iran has been used. For measuring the liquidity risk, the three criteria of the ratio of loans to deposit, the ratio of deposit composition and deposit ratio to assets have been used, and according to Khan et al (2016), risk taking of the bank has been using two benchmarks for the bank's book and market risk taking. The results of the research show that the interactive capital buffer and liquidity risk variable have a significant and reverse relationship with the bank's risk-taking. But the results of the research on the same effect of the legal reserve on the relationship between liquidity risk and market riskiness of the bank were only confirmed in the total deposits to total assets (the inverse criterion of risk-taking) criteria.