As the digital empowerment wave collides with the realities of an aging society, the question of whether enhancing older adults' digital literacy can translate into subjective well-being has become an unavoidable challenge for implementing active aging policies. Using data from the 2020 China Longitudinal Study of Aging Society (CLASS), this study examines the impact and mechanisms of digital literacy on older adults' subjective well-being. Findings reveal that digital literacy significantly enhances older adults' subjective well-being, with this effect remaining robust 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: expanding social participation and enhancing social adaptation. Additionally, a chained mediating effect exists between social participation and social adaptability. Based on these findings, we recommend prioritizing the enhancement of older adults' digital literacy as a key policy focus for active aging. This includes providing greater policy support for social participation among older adults,and accelerating community-based age-friendly renovations to enhance older adults' subjective well-being.