As a rational social activity of sharing information, observing the world and finding out the truth among human beings, journalistic activity is closely connected with argumentative thinking and practice, this is especially the case in present network society. On the basis of literature review, the paper studies journalism from the perspective of argumentation theory, to be specific, with the approach of pragma-dialectics. With this paradigm, the journalistic activity was taken as a critical discussion between journalistic subjects, and the propagating subjects as well as the receiving subjects included were seen as protagonists and antagonists respectively. What’s more, the accountabilities from both sides are strongly emphasized and certain rules are developed to be followed. The paper points out that the final realization of news authenticity benefits from critical discussions among journalistic subjects.