Aging and digitalization have become the two major characteristics of China today, and how to adapt and integrate the elderly into the digital society is one of the key points of active aging. Reality shows that when the long-term and complex nature of policy implementation and technological innovation requires sufficient conditional efficiency, and intergenerational support from families lags behind or even disappears, the play of peer effect becomes a digital support that cannot be ignored, and its own initiative, universality and sustainability can effectively promote digital integration. Using case analysis method, this article focuses on the elderly group who are driven by peer effect and complete the reconstruction and iteration of digital roles in the process of digital integration. They complete the transformation of digital integration under the multiple effects of environment, tools and interpersonal relationships. In order to fully tap the potential of peer effect to promote digital inclusion, a comprehensive analysis framework of “motivation triggering-mutual aid path-action mechanism” is constructed to observe and understand the behavioral patterns of the elderly group in the process of integration, and a triple mutual construction path of “motivation embedding-scene integration-action diffusion” is defined through participatory case observation. Furthermore, it further reveals that in the process of digital integration of the elderly group, peer mutual assistance is the core, and it is formed by multiple interactive relations with consensus and cooperative actions, and the continuous cycle mechanism of the three-dimensional integration of “mutual assistance subject-mutual assistance structure-mutual assistance model” is supported by the mutual construction, revealing the behavior logic of digital poverty alleviation for the “digital poor”. This paper deeply explores the formation mechanism of dynamic evolution, and then provides suggestions and countermeasures at different levels from the realistic dimension, in order to solve the problem of promoting the digital integration of the elderly group from a new perspective.