Emerging online discussions in a Weibo (micro-blogging) platform argue for the new possibility of online deliberation in Chinese cyberspace. In order to ascertain the extent to which this platform is being used, the author has conducted a case study to measure the quality of deliberation of an online discussion of genetically modified (GM) foods in the comment section of posts written by Mr. Cui and Mr. Fang on Tencent Weibo. In order to gain a comprehensive understanding of the data, both methods of Discourse Quality Index (DQI) and interview have been used. The findings of the research indicate that the online discussion fails to meet two necessary criteria of deliberation: rational and logical statements and consensus building. However, the study results are not totally negative, since the levels of interaction, information exchange, mutual understanding and neutral expression are relatively high. According to the author, in the contemporary stage, online authoritarian deliberation faces many problems in the PRC. At micro level, first, online expression is irrational and illogical; second, it is hard to reach consensus building; third, participants are stubborn to their pre-given wills; forth, some people are indifferent to online discussions. At macro level, first, most of the online discussions have low external impact on decision-making; second, the strong government control may hinder the development of online deliberation.