The 19th National Congress of the Communist Party of China put macroprudential policy in the same important position as monetary policy, and this paper constructs an extended BGG-DSGE model based on the monetary policy background of China's liquidity management, analyzes the monetary policy transmission channel of liquidity management, and discusses the effectiveness of macroprudential policy on this basis. It is found that the precise liquidity management of the central bank is the premise guarantee for the effectiveness of macro-prudential policies, and the ineffective liquidity management makes the real economy obtain liquidity, resulting in economic contraction, while the "debt-deflation" channel of enterprises under the financial accelerator mechanism resonates with the economic downturn and loan contraction, further aggravating economic volatility. Macroprudential supervision of loan-to-value ratio and capital adequacy ratio has financial stability effects, and loan-value ratio can be used in the real economy through reverse feedback mechanism to reduce corporate leverage.