This paper studies the price behaviors of IPO in China and analyses their causes by multi variable regression models. This paper finds that underpricing of IPO in China is the most serious in the world; there is “hot issue” market; underpricing of IPO has positive correlation with the market condition and market value, and negative correlation with the amount of raising fund, and no obvious correlation with the price earning ratio in China. This paper draws the conclusion that a marketable IPO system should be set up in China as soon as possible.