Against the background of the digital transformation of preschool education, digital personalized picture books have become an important carrier for cultivating children’s prosocial behaviors. This study focuses on the internal mechanism and practical paths of digital personalized picture books promoting young children’s sharing behavior. Findings show that deep personalization(name + image + scene) is significantly better than nominal personalization, which only replaces names; role identification serves as the core mediator connecting personalized reading and actual sharing behavior; AR interaction, repeated reading, and adult guidance can strengthen the effect of behavior transfer. Accordingly, this paper constructs a complete implementation path of “three-dimensional personalized design–multimodal interactive reading–layered adult guidance–situated behavior transfer,” providing a theoretical basis and operable solutions for kindergartens and families to use digital personalized picture books to improve young children’s sharing behavior.