Abstract: Objective: To explore the relationship between motor coordination and core symptoms in school-age children with attention deficit hyperactivity disorder(ADHD), and the mediating role of executive function was also investigated. Methods: 65ADHD children were screened from 1 781 students in grades 1—4 of a public primary school in Beijing by using the diagnostic criteria of the US Diagnostic and Statistical Manual of Mental Disorders(5th Edition)(DSM-V), and another 21 ADHD children were recruited from the psychiatric clinic of a tertiary hospital in Beijing, so a total of 86 children(68 boys and 18 girls) with an average age of 8.54±1.27 years were included in this study. The Attention Deficit/Hyperactivity Disorder Rating Scale(ADHD RS-IV), Behavior Rating Inventory of Executive Function(BRIEF) and the Movement Assessment Battery for Children-two Version(MABC-2) were used to assess the core symptoms, executive function, and motor coordination. SPSS 26.0 software was used to analyze Spearman rank correlation, and the nonparametric percentile bootstrap method corrected for bias was used to test the multiple mediation model, the significance level was α =0.05. Results: The motor coordination, executive function and core symptoms were significantly correlated with each other in ADHD children, and the manual ability predicted the symptoms of attention deficit directly and negatively(β =-0.205, P<0.05). The mediating role of monitoring factors in executive function was accounting for 32.69% of the mediating effect size. The multiple mediation effect model showed that the balance ability was significantly negatively predicted the symptoms of attention deficit, and the mediating effect of inhibitors in executive function was accounting for 46.45% of the mediating effect size. Conclusions: The motor coordination ability is closely related to the core symptoms in ADHD children, and executive function mediates between the two. Improving the fine ability of school-age children with ADHD promoted the development of their monitoring function, which in turn improved their core symptoms; Improving the balance ability of school-age children with ADHD, has a positive effect on inhibition function, and then improve their core symptoms. In order to alleviate the core symptoms of attention deficit in school-age children with ADHD, it is recommended that the corresponding exercise program should be designed for the improvement of monitoring and inhibition functions, and the exercise interventions should be carried out to improve fine motor skills and balance ability.