The study aims to learn whether microblog sentiments impact readers’ message commenting and sharing behaviors. Based on the searching volume on the five major web portals in China，24 public event cases were randomly selected from the 300 hottest public events in 2013. Sina Weibo was used as the platform for sampling microblog messages，and a total number of 7114 messages were sampled. Each of the sampled messages was further coded with respect to its sentiment polarity，strength of sentiment，subjects of sentiment，and microbloggers’ information；meanwhile，the number of comments and the counts of the message being shared were also recorded for each message. The study covers the subjects of each type of sentiment，the correlation between sentiment strength and other variables，and the factors that influence the commenting and sharing behaviors on the microblog.