This paper mainly explores the relation between initial returns and audits by the big four accounting firms (the Big Four) in China. The sample period is from January 2007 to December 2012 (the new accounting standards in China is implemented after January 2007 for integrating with the international standards), and selected 1,069 IPO firms listed in the Shanghai Stock Exchange and Shenzhen Stock Exchange in this paper.Many previous studies have proposed the Informational Hypothesis, which states that the initial returns of IPOs being audited by the Big Four are lower than those IPOs being audited by other accounting firms. Oppositely, this paper proposes the Snap-up Hypothesis due to consider the IPOs in mainland China are characterized by “three lows,”: the low reliability of audits being performed by non-Big Four, low proportion of IPOs audits being performed by the Big Four, and low balling ratio. These “three lows” features indicate that the Snap-up Hypothesis applies in the IPOs market of mainland China. In other words, the initial returns of the IPOs being audited by the Big Four are higher than those IPOs being audited by other accounting firms due to the Big Four have the superior reputations.This paper further collects the trading volumes and the turnover ratio on the first day, and selects the Big Four audited IPOs by snap-up tide. As above mentioned, because the snap-up tide and raised stock prices on the first-day listing, investors may purchase the shares when offering and sell them on the first-day listing to obtain considerable profits.