Objective: To investigate the prevalence and associated factors of depressive symptoms among middle and high school students in Zhejiang Province, so as to provide scientific basis for the implementation of depressive intervention. Methods: Based on the health status and associated factors of middle and high school students in the project "Monitoring of Common Diseases and Health Influencing Factors of Students" during 2018 to 2021, a total of 73 309 students including middle school, ordinary high school and vocational high school surveyed in 11 cities of Zhejiang Province were selected by multi stage stratified cluster random sampling method. From 2018 to 2021, there were 6 008, 21 917, 23 712 and 21 672 students, respectively. The Chi square test and Logistic regression model were used to analyze the influencing factors of depressive symptoms in middle and high school students. Results: From 2018 to 2021, depressive symptoms detection rate of middle school students was 14.8%, with higher rate in girls (17.1%) than in boys (12.7%), higher rate in high school (17.1% in ordinary high school, 17.6% in vocational high school) than middle school (12.5%)( χ 2=278.77, 327.22, P <0.05). Univariate analysis showed that there were statistically significant differences in depressive symptoms detection rate among middle school students with different years (2018: 16.7%，2019: 17.9% , 2020: 13.1%, 2021: 13.0%), residence (yes: 16.3%, no:13.5%), body mass index classification (not overweight or obesity: 14.8%, overweight: 14.2%, Obesity: 15.7%), weekly exercise days (0-2 d: 17.1%, 3-5 d: 12.5%, 6-7 d: 13.1%) and bullying (yes: 35.5%, no: 10.7%) ( χ 2=293.40, 118.35, 7.83, 287.24, 4 978.84, P <0.05). Multivariate Logistic regression analysis showed that female students, ordinary high schools, vocational high schools, obesity, school bullying were positively correlated with depression ( OR =1.65, 1.70, 1.60, 1.12, 5.21), exercise 3 to 5 days per week, exercise 6 to 7 days per week were negatively correlated with depression ( OR=0.77, 0.81, P <0.01). Conclusions Depressive symptoms among middle and high school students in Zhejiang Province are prominent. Strengthening mental health education for students and providing attention and support from families, schools, and society are essential steps to reduce the occurrence of depressive symptoms among these students.