The tightly regulated financial system after the 1933 banking crisis gradually eased the banking business restrictions, deposit insurance and interest rate control, driven by financial liberalization and the technological revolution. Under the joint influence of financial innovation and competitive pressure, the waves of large mergers and acquisitions (M&A) in the banking industry was set off. Basically, there is a lack of discussion into what impacts the financial deregulation of laws launched after the 1933 Great Recession would have on banking M&A. Therefore, this paper mainly use case analysis method to state that the financial deregulation plays a driving role in the promotion of banking M&A and the final market can reach the Pareto effect. Through the research on the effect of deregulation, this paper is of research significance to how the government can maintain the market stability, optimize the market structure and improve the market efficiency through financial supervision.