Serving social governance of new era is an important social responsibility for new media. Government affairs short video featuring county-level officials has quietly risen，bringing new opportunities for primary-level governance and rural revitalization. The study takes “County Mayor Douyin” as the research object，uses content analysis to evaluate its content production and account operations，and analyzes its new characteristics and trends. The study found that，compared with other government affairs Douyin，the character of “County Mayor Douyin” is mainly the county chief themselves；the content themes are mostly tourism promotion and poverty alleviation；the video scenes are mainly real shots of leisure life；the short vedios mainly construct regional identity and spread local culture. At the same time，“County Mayor Douyin” generally has problems such as fuzzy positioning，lack of operation and management，resulting in limited coverage and influence，and it presents the pattern of difference sequence. The emergence of “County Mayor Douyin” is the result of a joint transformation of user demands，platform ecology，and grassroots government. Essentially，it is a technology-driven and media-enabled government service transformation. It is also the new media that actively fulfills its social responsibilities and provides a new form of communication between the government and the public.