Coming into the era of Web 2.0, the Internet has already become one of the most important centres for online public opinion. These opinions could have imperative influence on the field of economy, politics and culture. However, since the information online might be heterogeneous, complicated, dynamic and open, a new technology was applied to in this study, which is known as Web Mining. Two events related to government corruption happened in 2009 were chosen as study objects in this study. Online public opinion of these two cases were mined and analyzed according to netizens varied intentions and standpoints, etc. Besides, traditional news reports on the two events were also analyzed for discussion on the role of traditional media and new-risen user-generated content.