Objective: To determine the relationship between mental sub-health and dietary behavior among Chinese adolescents, and to provide a scientific basis for improving adolescent mental sub-health through healthy dietary behavior. Methods: A total of 16 545 adolescents aged 13 to 22 years were sampled by random cluster sampling method in six administrative regions of China. A questionnaire survey was conducted to investigate adolescents’ dietary behaviors and mental sub-health status. Results: The proportion of boys consuming breakfast, snacks, carbonated drinks, vegetables, fish and dairy products was 76.2%, 20.2%, 19.0%, 78.4%, 52.4% and 59.2%, respectively, while the proportion of girls was 79.2%, 28.6%, 12.6%, 78.3%, 43.2% and 54.9%, respectively. Except for the "vegetable" option, dietary behaviors showed significant sex differences(χ2=20.79,320.10,229.06,150.27,32.21,P<0.01). In terms of mental sub-health, the detection rates of male adolescents’ mental sub-health status, behavioral sub-health and social sub-health were 20.7%, 26.0% and 17.2%, respectively, while those of female adolescents were 18.6%, 24.1% and 14.8%, respectively. The differences between boys and girls were statistically significant (χ2=17.32,7.66,17.46,P<0.01). Controlling for age and gender, breakfast "normally eating" and "occasionally eat", vegetables "normally eating" and "occasionally eat", fish "normally eating" and "occasionally eat", milk, dairy products "normally drink" and "occasional drink",was negatively associated with teenagers’ psychological sub-health (OR=0.60,0.73;0.50,0.65;0.74,0.77;0.73,0.69,P<0.05). Conclusion Healthy dietary behavior could be protective to avoid adolescent mental sub-health.Nutritional lectures and guideline books are needed among students and their parents.Nutritionists are encouraged to provide healthy nutritional advice to school canteen.