<p>University students in digital environments often experience a paradox between their desire to connect and their tendency to avoid social interaction. This study explores the relationships among three types of social motivation (intimacy, influence, and self-expression), appearance-based self-presentation anxiety, social fatigue, and social avoidance behavior among Chinese university students. This cross-sectional survey included 821 students from five universities in Zhengzhou, northern China, representing diverse academic disciplines. Standardized questionnaires were used to assess all variables. Data were analyzed using structural equation modeling. Results showed that all three forms of social motivation were indirectly associated with social avoidance through two parallel mediators: appearance-based self-presentation anxiety and social fatigue. Appearance-based self-presentation anxiety emerged as a strong mediator, amplifying avoidance behavior, while social fatigue further increased withdrawal tendencies. The findings reveal how social motivation can be linked to social avoidance under the emotional pressures of self-presentation in online contexts. This study offers empirical support for understanding students’ social coping mechanisms and suggests implications for designing psychological interventions in digitally connected higher education settings.</p>