In recent years, there have been more and more post-truth events. Government websites, government agencies, media and Internet users play different roles in the post-truth events. People are often influenced by factors, such as their positions, beliefs, values, and emotions, and the truth is submerged, obscured or delayed in the torrent of public opinion before it comes to surface. Hence the post-truth events will undoubtedly cast negative effects on the public opinion space and the real society. In this sense, the empirical analysis which investigates the major factors causing the post-truth events and its internal mechanisms, become an important and meaningful thing. It has important theoretical and practical significance. On the basis of clarifying the concept and connotation of the post-truth, this paper firstly analyzed the main generating factors of post-truth events. Firstly, we use a questionnaire to survey information acquisition channels, the degree of trust of information source, the degree of emotional expression ,the attitude towards events on the Internet and individual’s information. Using principal component analysis, this article analyzed the main generating factors and the internal mechanisms of post-truth events. Six factors were identified through principal component analysis, which includes ″unofficial trust″,″official trust″, ″official source″, ″social source″, ″attitude towards others″ and ″self-reflection″. Secondly, correlation was tested between the six factors and the dependent variable ″emotional expression of the audience″ by using the Pearson correlation test. Finally, this paper proposed countermeasures and suggestions to prevent post-truth events from the perspectives of government, media and audience.  The major factors that generate post-truth events include: the audience's information acquisition channels, the network public opinion atmosphere, the extent to which the online public opinion space accommodates different opinions, the willingness of the audience to pursue the truth, and the irrational or emotional expression of different opinions.〖JP2〗 The internal mechanisms in the generation of post-truth events are as follows: 1) Individuals obtain information from official, authoritative or unofficial, non-authoritative sources, and the multi-channel, multi-source information may exacerbate the individual's emotional expression tendency;〖JP〗 2) The online public opinion atmosphere will then have an impact on the individual judgment. This is especially true with emotion-oriented Internet paradoxes resulting in the ″Information Boudoir″ and ″Echo Room Effect″. Therefore, netizens are unwilling to accept opinions coming from different positions, beliefs, values, and especially different emotions, which hence accelerates the spread of emotional speeches; 3) Those who are not affected by the ″Silent Spiral Effect″ are calmer and more objective. These people present a lower emotional tendency when expressing dissent; 4) Meanwhile, the diversification of information channels leads to the fragmentation of information and the diminishing credibility of information. The complex and even radical network public opinions may cause the netizens to suspect the truth of the incident; 5) In the process of pursuing the truth of the incident, netizens are vulnerable to the ″sympathy for the weak″ and the pursuit of individual rights and interests, which intensify the individual's emotional expression. The emotional expression of many individuals in the online public opinion space transcends the truth of the event itself. The truth is thus obscured, distorted, derived, or over-deducted. As such, the government, the media, and the audience need to work together to avoid the generation and spread of post-truth events and prevent their risks and harms.