Objective: To investigate the prevalence of depression and anxiety symptoms among middle school students in Taizhou, Zhejiang Province, and its associations with their educational burden, so as to provide a theoretical reference for making more targeted psychological interventional measures. Methods: A cross sectional study was conducted by multi stage cluster sampling from September to November 2022 from 30 schools in five districts and counties of Taizhou, with a final sample of 8 128 junior and senior high school students completing the online surveys on the Questionnaire Star platform. The Educational Stress Scale for Adolescents (ESSA) was used to measure academic stress; the Child Depression Inventory (CDI) and the Generalized Anxiety Disorder Scale (GAD-7) were used to screen students depression and anxiety, respectively. The relationships between educational burden and depression and anxiety symptoms were analyzed by Logistic regression models. Results: The prevalence of depression and anxiety were 19.3% and 11.1%, respectively. The average score of middle school students study pressure was (52.8±11.5). The number of extracurricular classes was <1, the time length of extracurricular courses was <1 hour per day, and students averagely spend 3.6 hours per day on homework assigned by school teachers. Nearly 30.0% students had ≤0.5 of discretionary time school days and 28.5% students had ≤2 on weekends. About 30.8% students though they do worse in their academic performance. According to the results of binary Logistic regression analysis, after controlling the demographic variables, the score in Study Pressure Scale, the number of extracurricular classes, the volume of homework and the time length of extracurricular courses were positively associated with depression and anxiety ( OR =1.09, 1.07, 1.08, 1.05, 1.04, 1.08, 1.08, 1.08, 1.06, 1.09, 1.07, 1.47, 1.34, 2.84 ; 1.08, 1.06, 1.08, 1.04, 1.03, 1.05, 1.05, 1.05, 1.05, 1.07, 1.06, 1.48, 1.23, 1.75, P <0.05). Students with overage grades had a higher risk of depression symptoms ( OR=1.34, P <0.05). Conclusions Academic burden has negative effects on depression and anxiety of students in Taizhou. It is advisable to alleviate academic stress, so as to improve the mental health of students.