Objective: To understand the relationships between video time, exercise time and the mental sub-health of Chinese adolescents, and to assist the development of Chinese adolescents’ mental health. Methods: In this study, 16 545 adolescents aged 13-22 years in six administrative regions of China were surveyed using an adolescent sub-health multi-dimensional assessment questionnaire (MSQA), and daily physical exercise time, video screen time and other indicators were recorded. Binary Logistic regression analysis was used to understand adolescents’ mental sub-health and the correlation between video time and exercise time. Results: Detection rate of mental sub-health status in adolescents with video time ≤2 h/d was lower than that of adolescents with video time >2 h/d(19.1%，22.1%), and the detection rate of adolescents with exercise time ≤60 min/d(22.1%，17.7%) was higher than that of adolescents with exercise time >60 min/d. These differences were statistically significant (χ2=14.47, 6.97, P<0.05). Binary Logistic regression analysis showed that the risk of mental sub-health status for Chinese adolescents whose screen time was more than 2 h/d was 1.20 times that of those with screen time ≤2 h/d, and the difference was statistically significant (P<0.01). The risk of mental sub-health for students whose exercise time was > 60 min/d was 0.86 times that of students who exercised ≤ 60 min/d, and the difference was statistically significant (P<0.05). Conclusion Screen time >2 h/d and exercise time <60 min/d were negative factors leading to mental sub-health symptoms in Chinese adolescents.It is proposed to jointly promote the healthy adolescent development through health education,as well as positive family and social environment.