IPO underpricing has been the focus of financial research. But the causes of the IPO underpricing phenomenon haven't formed a unified understanding. The paper selected the 35 stocks of 119 companies to analyze which were successful IPO from 2009 January 1st to March 2010 and 19th in Shenzhen. The results showed that: the more the ownership dispersed, the lower the underpricing, the two were negatively correlated.