Since 2009，when Sina microblog inception，recent years，increasingly of microblog is showing a blowout development trend.The low threshold of microblog，kinds of distribution channels and the relaxed external regulation make microblog have the basic elements of the “public domain”.Recent years，the “grassroots” make their voice in the many public events through microblog.With the microblog，public opinion has played an increasingly important role in public events，Longing of the “Electronic Utopia” is also growing in popularity.The paper finds that microblog does not really change the right to speak in the Internet. Although microbloy has Strengthened some people’s right to speak，which referring in particular to the discourse of elites，the right of the “grassroots” to speak becomes more weaken.