With the rapid development of fintech globally in recent years, its low penetration rate among the elderly population has been increasingly emphasized. In response to the limitations of classical technology acceptance models (e.g., TAM, UTAUT) in explaining Fintech adoption among older adults, this study proposes a more structured and refined model of Fintech adoption among Chinese older adults based on the Theory of Planned Behavior (TPB). Through semi-structured interviews with 35 Chinese older adults, this study comprehensively analyzed the facilitating and hindering factors throughout the whole process from the first contact to the final decision to adopt or abandon consumer-oriented Fintech and wealth management Fintech, and refined the core constructs of attitude, subjective norm (SN), and perceived behavioral control (PBC) in TPB. The model provides a more comprehensive account of older adults’ motivations for Fintech adoption, clarifies the key dimension of perceived risk as a major hindrance, and enriches the connotation of SN and PBC. Compared to previous models, the new model proposed in this study enhances the understanding of the unique needs of Chinese older adults and the specific context of Fintech application, and is able to provide more targeted theoretical guidance for the promotion of Fintech among this population.