By using the method of case study, this paper empirically studied the difference between family business and nonfamily business on the disclosure of information and the possibilities of insidetrading. The result shows that for the good news, the cumulative abnormal return of family business was significantly higher than the nonfamily business (approximately higher 1.5%) in the 30 window periods before the announcement of the information. It illustrates that family business has a more obvious information leakage problem, the possibility of insider trading is much larger than the nonfamily business. But for the bad news, there is no significant difference between these two different equity structure firms.