The mining of network public opinion information is an important subject of public opinion research. To quickly discover useful public opinion information among a large amount of information and support public opinion analysis and corresponding decision-making, this study proposes a method of ranking the usefulness of public opinion information for specific viewpoints to achieve the purpose of quickly discovering useful public opinion information under specific viewpoints. This method analyzes and calculates the specific viewpoints of public opinion information and assigns scores to the information by a ranking method according to its credibility and attention and the influence of the disseminator with due consideration of the timeliness of the information and other factors. Then, the public information is ranked in terms of usefulness according to its score. The experimental results show that the proposed method performs well in the recommendation ranking of public opinion information. This research theoretically supplements the research theory of public opinion information mining. Concerning practical significance, it can well assist public opinion managers as it provides a boost to the guidance of network public opinions.