Contemporary China is experiencing deeper reform and social transformation. The newly born social media have participated in the historical process of China's reform and social change. Based on the existing literature of social media and internet public events, this article aims to study China's internet public events through the perspective of social transformation theory, especially theories of the civic society and public sphere. This study has used case study to explore the role that social media play in social change in China through in-depth analysis of 57 typical cases. We found that social media are not only an important information source and means for online civil mobilization, but also provide citizens an open and free space for discussion of internet public events. The impact of social media in promoting social change was reflected in the supervision of governmental, judiciary and other public power; maintenance of justice and protection of disadvantaged groups; attracting the government's attention, urging governmental information publicity and investigation of the events, and promoting social management innovation and institutional change. Social media are a helpful force in the construction of internet public sphere and civil society of contemporary China. Meanwhile, it is necessary to be cautious that social media is also likely to be a breeding ground for nationalist and populist discourses. (C) 2016 Elsevier Ltd. All rights reserved.