Research has shown that physical activity is linked with both physical and mental health outcomes. The present study examined two physical activity intensities and their relationship to stress and subjective well-being in a sample of mainland Chinese university students (N = 317; 54.9% female). Students completed a survey package in simplified Chinese measuring their leisure time physical activity, subjective well-being, perceived stress, and demographic variables. Two-step structural equation modelling was used to examine the relationships between vigorous and moderate intensity physical activity, and stress and subjective well-being. Sex and exercise as a mechanism to cope with stress were included as covariates in the final model. Moderate physical activity was significantly negatively related to stress (? = -.18), and also shared a relationship with subjective well-being (? = .11). Vigorous physical activity was related to stress (? = -.10). Although the latter two relationships did not meet the p < .05 cutoff, this research implies that physical activity may be used to mitigate stress and improve subjective well-being in Chinese students, and should be promoted by facilitators at Chinese institutions.