The purpose of this study is to analyze the effects of changes in capital adequacy ratio as a Macroprudential tool on the behavior of macroeconomics as well as the Iranian banking system. For this purpose, a Dynamic Stochastic General Equilibrium (DSGE) model is used and according to structural shocks, four observable variables including output gap, bank capital adequacy, inflation, and money base growth rate in the period spring 2004 to winter 2020, Along with some other pre-set parameters have been used in the Bayesian estimation process. Finally, the Impulse response functions of the model are interpreted in two scenarios Basel II or III on capital adequacy ratio. The results show that strengthening and improving the capital adequacy ratio in the short and medium term will have positive effects on economic growth and a significant reduction in inflation. The results also showed that Iranian banks react immediately to the strengthening of the capital adequacy ratio and try to adjust this ratio again by increasing lending. Therefore, in the medium and long term, we cannot hope to stabilize or reduce the process of creating liquidity and increase the money supply by strengthening the capital adequacy ratio of banks. Another finding of the model is that in the Iranian banking system, if the Capital adequacy ratio deviates from its equilibrium values, in the hypothetical conditions of the establishment of Basel III, macroeconomic variables and also the components of banking operations will face fewer fluctuations compared to Basel II.