This study aims to explore the impact of digital literacy on cognitive function among rural empty-nest older adults in China and its underlying mechanisms. Using data from the 2020 China Health and Retirement Longitudinal Study (CHARLS), 2 325 eligible rural empty-nest older adults aged 60 and above were selected as the sample to collect their digital literacy, social participation, depressive symptoms, cognitive function, education level, and related demographic data. Correlation analysis was used to examine relationships among variables, and the Process macro program was employed to test the chain-mediation effect of social participation and depression, as well as the moderating role of education level in the relationship between digital literacy and social participation. Results indicated that digital literacy can indirectly improve cognitive function among rural empty-nest older adults by promoting social participation and alleviating depressive symptoms, and education level strengthened this mechanism. The findings suggest that it is essential to focus on differences in educational backgrounds in efforts to improve digital literacy among rural empty-nest older adults. Tailored digital support strategies should be designed for different education groups to promote social participation, alleviate depressive symptoms, and delay cognitive decline.