In 2009, Ben Bernanke, chairman of the Federal Reserve, described shadow banking as a financial intermediary that converts savings into investments in addition to regulated deposit-taking institutions. To put it simply, the essence of shadow banking is a financial innovation that breaks through traditional financial institutions in order to maximize profits in the financial market environment. In this paper, we compare the U.S. and Chinese shadow banking system and their market system. From that, we analyze their similarities and differences from the aspects of emerging factors, classification and scale, and operation mode. Based on the above analysis, we then discuss the current situation of supervision of shadow banking in the United States and find that the U.S. shadow banking is negligent in institutional constraints and has practical difficulties in legal supervision. Finally, we put forward some suggestions on the future development and financial structure optimization of shadow banking.