PURPOSE: This study investigated whether abnormal cerebral activity observed in adolescents and adults with ADHD also occurs in children during the early developmental stages of executive function. METHODS: The study included 52 children with ADHD aged 4.0-9.0 years and 34 healthy control children. Changes in oxygenated hemoglobin (HbO) levels were measured while participants completed GO/NOGO tasks to assess brain activation and connectivity. RESULTS: Children with ADHD demonstrated a stable prefrontal activation deficit during the GO/NOGO tasks ( < 0.05). Additionally, hyperconnectivity was observed between the motor area and the prefrontal lobe in these children (uncorrected <0.01). The logistic regression model incorporating brain activation and connectivity features achieved an area under the ROC curve of 0.86 (95% CI, [0.78, 0.95]), with a sensitivity of 0.79 and specificity of 0.85. CONCLUSION: The findings suggest that prefrontal region abnormalities are present in children with ADHD at early developmental stages. This underscores the importance of targeting the prefrontal cortex in interventions and highlights the role of multi-network coordination in ADHD-related brain abnormalities. Limitations include the cross-sectional design and relatively small sample size, which should be addressed in future longitudinal studies.