Rumors always trigger public panic in China, while the advanced Internet technology has tremendously influenced the daily life of the Chinese. Thus, the dynamics of rumor spreading via the social media in China are worthwhile discussing. In order to fulfill the aim of this research, one of the prevalent Chinese social media sites, the Sina microblog, is introduced and analyzed within the context of the salt-buying frenzy incident that occurred in China in 2011. Various theoretical approaches, from the sociological and media studies perspectives, are introduced to form the framework for analysis. The relevant data and materials were collected via questionnaires with Chinese Internet users, while previous academic research and publications provide supportive materials. From the analysis of this social media site and contemporary Chinese circumstances, it was seen that the Guanxi network extended and enlarged the influence of online rumors to offline Chinese. In other words, the Guanxi network, expanded by social media, can be considered as the most important part of the dynamic process of rumor spreading in China. However, the openness and freedom of the Internet atmosphere were found to be the main factors in eliminating online rumors.