Objective: The aim of the study was to investigate the association of outdoor physical activity and insomnia symptoms with depressive symptoms in college students, so as to provide a theoretical basis for preventing and improving depression of the college students. Methods: A sample survey of 9 349 college students from 4 colleges and universities in 3 provinces in Hubei, Jiangxi and Chongqing were conducted from November to December 2021. The Patient Health Questionnaire, Insomnia Severity Index and outdoor physical activity questionnaire were used to evaluate the depressive symptoms, insomnia symptoms and outdoor activities of college students, respectively. The χ 2 test was used to compare the difference of the positive rate of depressive symptoms in college students. Logistic regression analysis was used to analyze the association between outdoor physical activity, insomnia symptoms and depressive symptoms. Generalized linear model was used to analyze the association of interaction effect of outdoor activity and insomnia symptoms with depressive symptoms. Results: The detection rate of depressive symptoms in college students was 37.4%. Significant differences in the detection rate of depressive symptoms were observed among college students with different majors, nationalities,educational backgrounds, family residence, family type, family economic conditions, study burden, number of friends, father s education level,mother s education level( P <0.05). Logistic regression analysis showed that outdoor physical activity ( OR=0.51-0.69, P <0.01) and insomnia symptoms ( OR=6.15-21.30, P <0.01) were associated with depressive symptoms( P <0.01). Generalized linear model showed that insomnia symptoms( B =0.57), outdoor physical activity ( B =-0.15) and their interaction terms ( B =-0.02) were associated with college students depression( P <0.05). Conclusion This study suggests that insufficient time for outdoor physical activity and insomnia symptoms may increase the risk of depressive symptoms in college students. College students with insufficient time for outdoor physical activity and insomnia have a higher risk of developing depressive symptoms.