Taking a loose monetary policy after the epidemic is an economic downturn. The persistence of the COVID-19 epidemic has brought negative impacts on the global economy. In this situation, central banks around the world have adopted a new round of loose monetary policy to counter the impact of the epidemic. Countries are faced with problems such as enterprise closure, consumption tightening, production stoppage, trade obstruction, supply chain interruption, etc. Economic recession seems to have become a high probability event.