Crisis events often endangered the stakeholder’s legitimate interests but applying the persuasion strategies properly can help solve this problem and promote the healthy development of relative industries. In order to explore the persuasion strategies in crisis events，this article which guided by Dorwin Cartwright’s four principle of persuasion mainly and the viewpoint of Hovland peripherally aimed at explaining the strategies used by the users of Xin Lang who posted the Microblog to sell watermelons during the storm of CPPU by using case study and comparative analysis. It concluded that the persuasion effects of Vulnerable Groups was better than powerful group，and kowtowing was better than defense and asked simple and clear information.