Objective: To explore the associations of physical activity and sleep quality with anxiety and depressive symptoms in college students, in order to provide empirical support and theoretical guidance for mental health intervention among college students. Methods: From March to April 2023, 2 099 college students from universities in 6 different provinces were selected by a convenient sampling method. Physical activity, sleep quality, anxiety and depressive symptoms were evaluated by the International Physical Activity Questionnaire Short Form (IPAQSF), the Pittsburgh Sleep Quality Index (PSQI), the Center for Epidemiologic Studies Depression Scale (CESD) and the Anxiety SelfRating Scale (SAS), respectively. Descriptive statistics and Logistic regression models were used to analyze the data. Results: The reporting rates of lowintensity, moderateintensity, and highintensity physical activity among college students were 30.3%, 45.3%, and 24.4%, respectively. Moreover, among the participants, anxiety was detected in 21.6% and depressive symptoms in 39.9%, while 62.3% experienced poor sleep quality. Compared with males, females exhibited a lower proportion of highintensity physical activity (22.3% vs 42.8%), while reported higher proportions of moderateintensity (48.1% vs 40.8%) and lowintensity physical activity (29.5% vs 16.4%). Additionally, the proportion of females reporting poor sleep quality (65.0%) was higher than that of males (58.0%) (χ2=110.15, 10.70, P<0.05). The proportion of girls (43.8%) with depressive sypmtoms was higher than that of boys (33.9%) (χ2=20.48, P<0.05). Logistic regression analysis showed that high physical activity was negatively correlated with anxiety and depression (OR=0.45, 0.33), poor sleep quality was positively correlated with anxiety and depressive symptoms (OR=3.89, 3.94) (P<0.01).The interaction effect between high physical activity and good sleep quality was associated with the reduction of anxiety and depression among college students (OR=0.14, 0.08, P<0.01). Conclusions Physical activity and sleep quality are associated with anxiety and depressive symptoms among college students. The interventions for mental health problems such as depression and anxiety among college students should aim to improve physical activity and sleep quality.