Abstract: With the acceleration of population aging and the integration of digital technology, the digital reading behavior of the elderly has become a research focus. This article integrates social cognitive theory and self-determination theory, focusing on the influencing factors and dynamic mechanisms of digital reading behavior among the elderly. Using the grounded theory method, in-depth interviews were conducted with 30 elderly people aged 60 and above, and a three-dimensional theoretical model of "environment individual behavior" was constructed. Research has found that the digital reading behavior of elderly people is the result of multiple dynamic interactions, among which supportive environments reduce challenges, stimulate needs, and positively promote behavior; Restrictive environments exacerbate challenges, suppress demand, and intervene negatively; The content environment of digital reading platforms affects the depth of usage by adjusting the quality and promotion of content. And propose to help the elderly shift from "passive adaptation" to "active integration" by strengthening policy coordination, breaking down cultural and technological barriers, and optimizing content ecology.