As one of the tools to stimulate the economic growth, quantitative easing (QE) has been used by some countries like Japan, the United States, etc. Whether it does good or bad to the economy is to be further discussed. The paper first provided an overview of QE that was initiated in the United States, then compared the theoretic anticipation and the practical operational outcomes of QE. Finally, the paper drew conclusions about the impacts of QE to the global economy.