<p>This study aims to investigate the impact of physical activity on problematic internet use and to reveal the mediating role of self-control and psychological distress in the path relationship between them, providing a theoretical foundation for reducing problematic internet use and promoting mental health among college students. This cross-sectional study was conducted with undergraduate students. Data were collected online using network sampling through the online survey platform Google Forms. Data were collected using the Demographic Data Form (DDF), Physical Activity Scale-2 (PAS-2), the Addiction Profile Index Internet Addiction Form (BAPINT), the Brief Self-Control Scale (BSCS), and the Psychological Distress Scale (K10-PDS). In order to evaluate the adequacy of the research model, path analysis, a component of structural equation modeling (SEM), was used using AMOS software. The structural model also exhibits a good fit, with x² /df = 3.105, RMSEA = 0.081, GFI = 0.964, AGFI = 0.924, CFI = 0.948, TLI = 0.914, and IFI = 0.949. Physical activity could directly negatively predict the problematic internet use of college students. Self control and distress partially mediate the relationship between physical activity and problematic internet use, and the mediating pathways included “physical activiy-self control- problematic internet use”, “physical activity-distress- problematic internet use”, and “physical activity-self conrtol-distress- problematic internet use”, accounting for 12.6%, 33.7% and 4.7% of the total effect, respectively. The results of this study provide an important framework for understanding internet addiction in this population, supporting the I-PACE model.</p>