Objective: To explore the association between physical activity levels and depressive symptoms among college students, so as to provide evidence for promoting physical and mental health of college students. Methods: Using a cohort study design,a baseline survey of 1 415 college students in Shenyang Normal University in 2017 followed for three years from 2018 to 2020. The International Physical Activity Questionnaire-Short Form (IPAQ-SF) and Selfrating Depression Scale (SDS) were used to evaluate the physical activity levels and depressive symptoms of college students. According to the level of physical activity at baseline (MET ·h/week), participants were divided into three groups [T1 (≤36.4), T2 (>36.4-89.3) and T3 (>89.3)]. Logistic regression analysis was used to examine the association between baseline physical activity levels and the incidence of depressive symptoms during the school years. Results: In the 3year followup (2018-2020), 852 (60.2%) participants exhibited depressive symptoms. The numbers of individuals with depressive symptoms in the T1, T2, and T3 groups were 324, 268, and 260, respectively. Logistic regression analysis showed that college students who participated in higher levels of physical activity decreased the risk of depressive symptoms by 34.2% [T2: OR(95%CI) = 0.658 (0.500-0.866)] and 38.9% [T3:OR(95%CI)=0.611(0.465-0.804)] compared with T1 group after adjusting for demographic, lifestyle, healthrelated factors, and baseline depressive symptoms as covariates. The sexstratified analysis showed a negative correlation between physical activity levels and the incidence of depressive symptoms in female college students. Compared with T1 group, higher levels of physical activity reduced the incidence of depressive symptoms by 39.6% [T2: OR(95%CI)=0.604(0.445-0.820)] and 37.7% [T3: OR(95%CI)=0.623(0.459-0.846)], respectively (P<0.01). However, there was no significant correlation between physical activity levels and depressive symptoms in male college students (P>0.05). Conclusions There is an inverse relationship between physical activity levels and depressive symptoms. The findings suggest that schools should reduce the risk of depressive symptoms by promoting physical activity levels among college students.