Capital adequacy ratio and monetary policy are important control measures of financial supervisory authority and monetary authority, respectively. The effective coordination of the two has greatly affected the effectiveness of monetary policy. The article selects the annual data of 16 listed commercial banks in China from 2003 to 2018, and studies the impact of capital adequacy ratio on monetary policy transmission by constructor. listed commercial banks in China from 2003 to 2018, and studies the impact of capital adequacy ratio on monetary policy transmission by constructing a panel regression model. The results show that large state-owned commercial banks play a major role in bank credit channels for monetary policy, and banks with higher capital adequacy ratios are more likely to have a higher capital adequacy ratio. The results show that large state-owned commercial banks play a major role in bank credit channels for monetary policy, and banks with higher capital adequacy ratios are more vulnerable to monetary policy shocks. In addition, the external capital constraint of minimum capital adequacy will cause a multiplier effect when monetary policy is transmitted through credit channels. The multiplier effect produced by joint-stock commercial banks is much smaller than that of large state-owned banks. The multiplier effect produced by joint-stock commercial banks is much smaller than that of large state-owned banks. Therefore, financial supervisory departments must fully consider the interference caused by the capital adequacy ratio on monetary policy, strengthen policy coordination, and unblock the transmission mechanism of Therefore, financial supervision departments must fully consider the interference caused by the capital adequacy ratio on monetary policy, strengthen policy coordination, and unblock the transmission mechanism of monetary policy.