Using data from the 2020 China Longitudinal Aging Social Survey (CLASS), this study examines the impact and mechanisms of digital literacy on older adults’subjective well-being. Findings reveal that digital literacy significantly enhances the subjective well-being among older adults, with this effect remaining consistent after controlling for individual characteristics, family, and societal factors. Further mechanism analysis indicates that digital literacy improves subjective well - being through two independent mediating effects, including expanding social participation and enhancing social adaptability. Additionally, a chain mediation effect exists between social participation and social adaptability. Based on these findings, this study recommends prioritizing the enhancement of digital literacy among older adults as a key policy focus for active aging. This includes providing increased policy support for social participation among older adults, and accelerating community-based age-friendly renovations, thereby enhancing the subjective well-being of older adults.