Objective:To explore the clinical application of Conners’ kiddie continuous performance test (K-CPT) on diagnosis in preschool children with attention deficit hyperactivity(ADHD). Methods:Using the diagnostic and statistical manual of Mental disorders (DSM-IV) as a gold standard,K-CPT and parent symptom questionnaire(PSQ) were tested in 41 cases of preschool children with ADHD and evaluated. Results:Compared with DSM-IV,the sensitivity for K-CPT in diagnosing ADHD reached 73.3%,specificity for K-CPT was 81.8%,the false negative rate was 26.7%,and the false positive rate was 18.2%. The coincidence rate amounted 75.7%. The value of kappa was 0.470 (P < 0.001). There is no significant difference(P > 0.05) in the detection rate of K-CPT and PSQ. Discussion:K-CPT could be used as an objective diagnostic tool and applied in diagnosis of preschool ADHD.