This paper takes a PSA video in Youku as the study case to analyze the characteristics of netizens’ spontaneously initiating communication and participation behaviors, combining with one of the main problems in current Chinese PSA model, namely the lack of public participating enthusiasm during the whole process. It finds out that, as a result of the wide communicating time and space, subversion under the context of postmodernism and normalization of the oppositional code in internet, the participation and interaction of internet technology could not solve the lack of public participation in the PSA model as many optimists expected. It claims that only by improving from the reality and integrating citizens organically during the whole operating process could the problem be solved and the reduction effect to traditional channel be avoided.