There are some problems in the economy and society, which cannot be adjusted only by the market mechanism, so the intervention of the state is needed, that is, the "visible hand" of Keynes. Fiscal policy and monetary policy are the two basic means of macro-control. But why tax policy when the state can print money? Can we start the "money printing mode" and rely solely on new money to adjust the economy? The COVID-19 is one of the most disturbing issues for all human beings during recent years, even though the virus destructiveness was weakened due to the effort paid by the experts and governments worldwide. The corresponding issue is still quite severed and obvious. This template is specifically motivated to demonstrate the Fed fluctuated rate hikes under the impact of the COVID-19, which will briefly recap on the stagnant economic atmosphere of the United States. After finish reading this essay. Readers will get clearly and sufficient understanding on how does the national economy in the United States is changed due to several different factors, since the COVID-19 sparked at the end of the year 2019, and expounds the advantages of tax policy and the advantages and disadvantages of issuing more money, and concludes that the problem can be solved not only by printing money, but also by comprehensive use of various economic adjustment means.