Objective: To analyze the prevalence of overweight, obesity and depression among students in the Inner Mongolia Autonomous Region in 2019-2022 and explore the relevant factors affecting the co-morbidity of overweight,obesity and depression among students, so as to provide scientific basis for the prevention of co-morbidity. Methods: From September 2019 to 2022, used stratified random cluster sampling, 90 519,71 560,90 079,91 089 students were selected from all 12 leagues in Inner Mongolia Autonomous Region for questionnaire survey and physical examination. The χ 2 test was used for demographic characteristics and univariate analysis, and a binary Logistic regression model was used to explore the association between lifestyle behaviors and co-morbidity. Results: The detection rate of overweight,obesity among students from 2019-2022 was 29.21%,34.38%,35.20%,34.61%, the detection rate of depression was 18.35%，17.53%，16.43%，16.00%, and the co-morbidity detection rate of the two was 5.52%，5.93%，5.76%，5.46%. The number of overweight,obesity and depression co-morbidity students in 2022 was 4 978 students, and the co-morbidity detection rates of the students were significantly different in terms of the school segments and the family structures ( χ 2=103.51, 99.90, P <0.01). Multivariate Logistic regression analysis showed that consuming sugar sweetened beverages or fried food ≥1 time/d, sometimes or never eat breakfast, watching computer or TV ≥2 h/d, and less than 1 h of moderate-to-vigorous physical activity on weekends were positively correlated with the occurrence of the co-morbidity of overweight,obesity and depression, with the value of OR ranging from 1.17 to 1.59 ( P <0.05). Eated fresh fruits or drinking milk and soy milk ≥1 time/d, outdoor activities ≥1 h/d, sleep ≥8 h/d, not smoking and not drinking alcohol were negatively correlated with the occurrence of comorbid overweight,obesity and depression, with the value of OR ranging from 0.47 to 0.92 ( P < 0.05). Conclusion The occurrence of overweight,obesity and depressive symptoms co-morbidity in students is associated with dietary, exercise and lifestyle behavior. Targeted measures should be taken to maintain students healthy weight and prevent the occurrence of depression from the aspects of diet, exercise and life habits.