In 2008,the financial Tsunami spreads through all of the world. In the view of behavior finance, this thesis wants to use the method which was created by Weber and Camerer(1998)to examine whether all kinds of investors will show disposition effect. The research of the time is from 19/5/2008 to 15/1/2010, and we separate the period into bull market and bear market. And we also study all kinds of investors¡¦trading volume. According to the research results, the findings are listed as below: 1. All kinds of investors showp disposition effect, and the private investors would show disposition effect. 2. All kinds of investors would show bigger disposition effect for the smaller companies than for the bigger companies. 3.The disposition effect of dealers are similar to the private investors, but our research can not find out whether the stocks of their holding and rate of return are different from private investors. Keywords: behavior finance, disposition effect, over confident, cognitive bias