My dissertation will explore the origins of mass nationalism in China during the 1911 Revolution era. Specifically, I will study the political rhetoric and practices of Sichuan Province's Railway Protection Movement (1905-1911), which entailed unprecedented grassroots participation and the emergence of a new popular nationalism. Mass politics and popular nationalism are the two greatest driving forces of Chinese history in the twentieth century. Nationalism energized mass politics, and they together led to the success of the Communist Revolution. While scholars have only studied mass nationalism of the 1930s, I will investigate primitive elements of popular nationalism in the 1900s when new nationalist repertoires were first developed and rudiments of the later mass politics first started. I will especially investigate the political and cultural inventions that were formulated in this mass protest movement: What political repertoires were created? How did people link up and connect with each other? What kind of communication and rituals helped in cutting through boundaries of village, clan, and social class and bonding them together? In the heat of this political conflict, how did the mass participation and popular mobilization change the structure of the polity and transform the ways politics was conducted? How did the notion of “politics" change shape? To gauge the extent and effects of the 1911 Revolution, I employ archival research and interview records to bring to light the experiences of this movement. Constantly interacting with the cutting-edge theories on nationalism, political culture and collective action and actively drawing upon comparisons to the rest of the world, this dissertation serves to not only to cast new light on the most powerful forces for China's historical changes in the twentieth century, but also deepen our understanding of the nation formation movement in the beginning of the twentieth century as a world phenomenon.