The project proposes to develop a digital product based on cognitive behavioral therapy for the assisted treatment of depression. The digital cognitive behavioral therapy in this study is conducted based on a self-developed mobile applet. The therapy is developed by psychotherapists, which is conducted for a total of 8 weeks, with weekly sessions including AI-guided course work and homework. This study aims to evaluate the therapeutic effects of CBT-based digital products for depression in patients through a real-world study, and to explore its genetic and neuroimaging mechanisms.