The introduction of the first Basel Accord in 1988 marked a worldwide adoption of minimum capital requirements that had to be met at all times. This research explores the macroeconomic and monetary policy implications of the Basel I and Basel II systems of risk-based capital requirements. Regulatory tightening of capital ratios can generate aggregate shocks，which capital regulation can enhance the procyclicality already inherent in banking，and that capital requirements can influence macroeconomic outcomes and alter the monetary policy transmission mechanism. It is necessary for China to pay attention to the procyclical effect of capital adequacy requirements and different reaction between state-controlled commercial banks and other commercial banks. The paper offers suggestions for future avenues of research on the interplay between bank capital regulation，the economy，and monetary policymaking.