With the increasing popularity of the social network, public awareness and participation to hot topics has been much improved, mobile terminal equipment and fast Internet access make the spread of public opinion quickly. Public opinion on the Web has freedom, interactivity, diversity, deviation and burstiness as characteristics, has become an important factor that affects social stability. Therefore, how to timely detect, control and guide the development of public opinion is of great significance to the social stability. This article focuses on the behaviors that spread on the Web and contain “destruction”, “dangerous” and “loss” involves public security or judicial justice, and the behaviors is defined as abnormal behavior. We define the types of abnormal behavior that this article focuses on are aggression, injury, death, and arrests, four categories. From the point of view of information extraction, our method recognizes the abnormal behavior by identifying sentences that contain the abnormal behavior and constructs co-occurrence network of abnormal behavior, with provide the visualization analysis approach of public opinion on the Web.