 The study tested the clinical effectiveness and non-clinical performance of a CBT-based mental health chatbot, Xiaoyi, for young adults with depressive symptoms during the COVID-19 pandemic. The results showed that Xiaoyi was effective in reducing depressive symptoms, improving working alliance and increasing acceptability compared to an e-book and general chatbot group. However, no significant difference was found for usability. Further evidence is needed to confirm the long-term effectiveness of Xiaoyi and explore its stronger efficacy in comparison with other active controls. This article was authored by Yuhao He, Li Yong, Xia Kunzhu, and others.