From the perspective of "discourse representation" and "narrative construction ", this article carries on case study about the freedom of the press on micro blog, which is aimed to reveal the way through which micro blog constructs the press freedom discourse. The paper first examines the identity of the micro blog users, and then analyzes the narrative pattern and discourse practice on freedom of the press. The study finds that people mainly talk about press freedom from the following three dimensions: first is explain the press freedom from the perspective of contradictory relationship between government, media and the public ; second is the tendency of pessimism and nostalgia doctrine about the discourse of the press freedom; and the American centralism is the third narrative patterns. On the basis of these three dimensions, there are several ways to construct the freedom of press in the representation system: First, the construction of difference; the second is the construction of similarity; the third is the establishment of reference; the fourth is reset context; the fifth is filled with examples.