Despite the rising prevalence of online collective behaviors in Mainland China, there is a dearth of research on their categorization and underlying motivations. To fill this gap, we applied grounded theory to identify the major categories of online collective behaviors in China, and conducted a survey study to understand their underlying motivations. Results show Chinese online collective behaviors may take the form of hard, violent confrontations (e.g., burst-the-bar attacks), or soft actions (e.g., discussions and voting). In addition, some of these behaviors are geared toward restoration of justice in the social, moral, and political domains (justice-driven behaviors). Others are directed toward sanctioning counter-normative behaviors, or getting even with aggression against the in-group (intolerance-motivated behaviors). Individuals who intend to participate in justice-driven online collective behaviors perceive the social problems in China to be serious and to need to be addressed collectively. In contrast, individuals who participate in intolerance-motivated online collective behaviors are those who experience social estrangement. The intention to engage in both types of online collective behaviors increases with the amount of offline social influence.