Objective: To explore the dose-response relationship between duration of emotional experience of primary school students and the intensity of anxiety disorders, and to understand the risk of anxiety disorders corresponding to different emotional state levels. Methods: A total of 7 152 primary students from grade 3 to 5 were investigated with questionnaire survey from 16 public primary schools, by using the Screen for Child Anxiety Related Emotional Disorder (SCARED) and Positive Affect and Negative Affect Scale. Results: The prevalence of anxiety disorders was 19.91%, among which the prevalence rates of anxiety disorders in boys and girls were 19.41% and 20.43%, respectively. After adjusting for gender, grade, household register, the only child, parental marital status, parental occupation, parental educational level, family financial level, serving as a class leader, receiving special training or counseling in sports and art, and being bullied, the risk of anxiety disorder in children with positive emotions lasting for 7-16 days, 17-24 days and >24 days was lower compared to those with positive emotions lasting for less than 6 days(P<0.05); the risk of anxiety disorder in children with negative emotions lasting for 0.27-0.93 day, 0.94-2 days and >2 days was higher compared to those with negative emotions lasting less than 0.26 day(P<0.05). Restricted cubic spline analysis showed that the duration of emotional state and anxiety disorder showed a significant non-linear dose-response relationship (non-linear test, P<0.01), that is, as the number of days of positive emotions increases, the risk of anxiety disorder continues to decrease, and as the number of days of negative emotions increases, the risk of anxiety disorder continues to increase. Conclusion There is a significant dose-response relationship between the duration of the emotional state of primary school students and the prevalence of anxiety disorders. Acquirement and maintain positive emotions m be an important entry point for mental health promotion among primary school students.