My dissertation investigates public opinion and the nature of the public sphere in China by studying online discourse between 2009 and 2017. I ask what consensuses and cleavages have characterized the Chinese public sphere since the late 2000s, and what the structure of China’s ideological spectrum is. What sets this dissertation apart from previous studies about public opinion and ideology is three-fold. First, I study public opinion through the lens of opinion leaders. I argue that opinion leaders are the most important actors in the public sphere as they play a crucial role in leading and shaping public opinion, especially in an authoritarian context. Second, I combine large-scale social network data and textual data to investigate online opinion and to identify the structure of an ideological spectrum that captures these opinions. To start with, I estimate a left-right ideological axis based on social network data. Then I add other dimensions of the ideological spectrum by delving into the variations in online discourses. Eventually, I revisit the dimensionality of ideology and propose a new framework for understanding ideology. Third, I disaggregate public opinion into different topic domains. In particular, I investigate people’s opinions on nationalistic topics, their understandings of democracy and visions for an ideal political system, and their expectations for the socio-economic system. By combining different aspects of public opinion and juxtaposing people’s voices across issues, I am able to uncover the multiplicity of public discourse in China. This investigation is based on online discourse produced on a daily basis between 2009 and 2017. Through a multi-faceted long-term analysis drawing on large-scale data, I find that the Chinese public sphere is not dominated by pro-government nationalist discourse, but instead presents a consensus for economic and political reforms. However, underneath this consensus, there are a full range of political discourses that represent combinations of different, even seemingly conflicting opinions. For instance, nationalists may draw on liberal discourse to criticize the government for domestic social problems. Supporters of democracy may express pro-regime opinions when they talk about issues pertinent to social stability and economic prosperity. Such multiplicity and complexities of Chinese public opinion highlight an important finding of this dissertation: the common assumption that Chinese public opinion is polarized between pro-regime nationalism and anti-regime activism is not supported by empirical data. Instead, public opinion demonstrates cross-cutting consensus and cleavages. While a majority of opinion leaders deem political reforms necessary, they envision the future of China in fundamentally different ways and have a different order of priorities. This ironically prevents citizens from mobilizing and forging a united effort pushing for one clear agenda. Implications for the nature of ideological preferences and the nature of the public sphere in China are discussed at the end of the dissertation.