<p>Environmental issues are associated with the pursuit of sustainable development in human society. To address environmental challenges, it is crucial to encourage residents to engage in pro-environmental behaviors. Instead of investigating residents’ offline pro-environmental behaviors, this study focuses on residents’ online green behavior by examining their Ant Forest use behavior. Ant Forest is an environmental protection online platform widely used in China. A total of 505 samples is obtained using a convenience sampling approach for this study. The research findings suggest that environmental risk perception has a positive impact on residents’ online green behavior. Social trust exerts a positive effect on residents’ online green behavior. More importantly, social trust partially mediates the effect of environmental risk perception on online green behavior. Unlike traditional offline pro-environmental activities, Ant Forest users need more trust and psychological support to overcome the concerns of pro-environmental engagement and supervision. Additionally, this research provides managerial implications for Ant Forest designers and environment managers enhancing Ant forest content design and promoting more pro-environmental behaviors.</p>