Following the boom of the internet, the widespread participation of Chinese internet users has led to the emergence of network public opinion. Many public events are quickly magnified and widely spread on the internet, finally evolving into mass incidents. The generation and development of network public opinion are very complicated. Based on literature review, the main factors affecting the network public opinion are summarized, and they comprise the subjective factors and objective factor. To be specific, they include government's ability of response to network public opinion, media communication, netizens' attitude, event, and communication technology. Taking MERS as an example, network questionnaire survey is utilized to build a structural equation model and study the five factors. There are direct and indirect relations among them. Then, the relation between network public opinion and mass incidents is explored. Finally, based on the findings, this paper provides some suggestions for the management of network public opinion from three aspects, namely the government, media management and guidance for internet users.