Background To investigate the value of the SNAP-IV scale combined with IVA-CPT objective attention/executive function indicators in identifying the risk of cognitive ability in children with ADHD, and to evaluate its incremental predictive ability over traditional subjective scales, providing a basis for clinical screening and stratified interventions. Methods A total of 248 children with ADHD (191 boys, 57 girls), with a mean age of 8.98 ± 1.68 years, were enrolled from the ADHD outpatient clinic at the Children's Health Center of Capital center for Children's Health, Capital Medical University. All participants completed the SNAP-IV scale, WISC and IVA-CPT Attention Test. Cognitive high-risk was defined by a Wechsler Full Scale IQ < 85. A logistic regression model (Model 1) was constructed including only the SNAP-IV total score, age, sex, parental ADHD status, and whether the child was an only child. Model 2 was constructed by adding IVA-CPT composite scores for attention quotient, response control quotient, and auditory/visual attention and control quotients. The area under the curve (AUC) of the ROC curve and DCA curve was compared between the two models. Results The AUC of Model 1 was 0.612, with a sensitivity of 0.804, and specificity of 0.426, indicating that its predictive ability for cognitive high-risk was close to random. After incorporating IVA indicators, the AUC of Model 2 improved to 0.707, with a sensitivity of 0.587, and specificity of 0.787, which was significantly superior to Model 1 (p = 0.034). DCA analysis further demonstrated that Model 2 offered more favorable guidance for decision-making at moderate-risk thresholds.Additionally, no significant correlation was found between the SNAP-IV score and any IVA dimension score, indicating that subjective symptom scales and objective attention function indicators assess different aspects of cognitive performance. Conclusion The SNAP-IV scale alone is insufficient for effectively identifying the cognitive high-risk individuals among children with ADHD. However, the addition of IVA-CPT attention and response control indicators significantly improves predictive performance. This study supports the use of a combined screening strategy of "subjective behavioral scales + objective cognitive tests" in ADHD assessments, which can help identify cognitive high-risk children early and facilitate early intervention. Trial registration Not applicable.