Nationalism campaigns are often aroused in online communities who also provide the avenue for the activists to march on. This phenomenon coincides with the operation mode of fandom groups in the internet era. This study investigated the development and spread of the “Fandom Girls Campaigns”, which were fan groups’ voluntary online actions without sophisticated organization,by crawling and analyzing related data obtained from Sina Weibo. The results suggested that the capability of fan groups to motivate and to spread was overestimated. The key influencers were traditional media with online accounts. The official online accounts of traditional media had demonstration effects on regular users and motivate them to participate. Later on, opinion leaders from different fields contributed to the deep spread of the event. Through social network analysis, we found that the main body of the spread was the consensus spread network with short spread chains; meanwhile, a few of the dissent network had longer spread chains.