In this article, the author tries to explore the effect of buiding brand trust through microblogging Corporate Social Responsibility. The author samples three business users of microblogging CSR from Weibo.cn, among which are: @dellcsr, @zlgoodlife, @ditan100. Then two corpuses are built by collecting: a) the texts blogged by the business users during six consecutive months in 2012; b) the texts blogged by other Weibo users as feedback to business users (comment, forward, mention@) during the same period. With assistance of corpus linguistic tool Concordance 3.3, the author conducting qualitative context analysis to both corpuses. The result shows that the more corporate microblogs offline CSR activities, the more brand trust online stakeholders (Weibo users) express. However, this online brand trust would most likely be harmed by followers’ unpleasant product experience.