Objective: To analyze the relationship between screen time and gross motor development and to provide scientific basis for health promotion among preschool children. Methods: In March 2021, gross motor of 373 children from 5 kindergartens in Baotou was tested by Test of Gross Motor Development (TGMD). Screen time (ST) was collected by parental questionnaire. Paired t-test was used to compare the screen time between working days and weekends, and independent sample t-test was used to compare the differences of children s motor development between different sexes. Results: ST of children was (52.10±31.67) min/d during the week and (65.79±10.36) min/d during the weekend. There were significant differences in the total scores of gross motor and mobile motor of children in different sexes( t=2.35, 2.65, P <0.05). The correlation between total screen time and gross motor, mobile motor and operant motor was statistically significant ( r =-0.22--0.20, P <0.01). Multiple linear regression showed that the time spent watching TV and the time spent using mobile phones during the week were the main factors affecting the gross motor development. Conclusion There is a significant negative correlation between children s screen time and gross motor development. It is important to reduce the time spent on TV and mobile phone to improve childhood gross motor development.