Objective: To explore the association between digital devices usage and body weight overestimation in children and adolescents aged 7-18, in order to provide a scientific basis for body weight overestimation prevention in children and adolescents. Methods: Based on the data of the Research Special Project for Public Welfare Industry of Health using stratified cluster sampling method in 2012, a tatal of 40 073 children and adolescents from 7 provinces with complete information were chosen. Ordinal multivariable Logistic regression model estimated the association between digital devices usage and body weight overestimation. Results: A total of 4 276(11.8%) students with overestimation of body weight were detected, who spent >300 min/d time in digital devices(5.12%) than others (3.84%)( χ 2=19.14, P <0.01). Univariate analysis showed that students with time spent on digital devices >300 min/d had a higher risk in overestimation of body weight ( OR=1.36,95%CI=1.18-1.57,P <0.01) compared with students who spent on digital devices≤120 min/d. There was still a significant association after confounder adjustment ( OR=1.28, 95%CI= 1.10-1.48,P <0.05). Stratified analysis showed that the association between digital devices usage and overestimation of body weight were only observed in girls, 11-18 years old and non single child( P <0.05). Conclusion The time usage of digital devices is associated with overestimation of body weight in children and adolescents. It may helpful for children and adolescents to prevent overestimation of body weight by reducing time spent on digital devices.