Objective: To investigate the attention cognitive function and symptom correlations of school aged children with attention deficit hyperactivity disorder (ADHD)using event related potential (ERP) technology, so as to provide references for the early diagnosis of children with ADHD. Methods: A total of 52 school aged children diagnosed with ADHD at the outpatient department of the Third Affiliated Hospital of Zhengzhou University from September 2022 to September 2024 and 50 age /sex matched healthy controls were selected. The ERP experiment adopted the auditory Oddball task to conduct comparative analyses of the amplitude and latency of the mismatch negative(MMN) at the Fz, Cz, and Pz points of the scalp electrode and the P3a component respectively. The symptom assessment scales adopted the Swanson,Nolan,and Pelham-Ⅳ Rating Scale (SNAP-Ⅳ) and the Parent Symptom Questionnaire (PSQ), which were filled out by the parents. Spearman correlation analysis was used to analyze the correlation between ERP components and symptoms in schoolaged children with ADHD. Results: The latency of MMN components in the healthy control group on the Fz lead was (188.30±2.06)ms, and the amplitude was (-15.54±1.35)μV; the latency of the P3a component on the Pz lead was (312.82±7.80)ms, and the amplitude was (3.80±0.18)μV. The latency of MMN components in the ADHD group on the Fz lead was (188.94±1.39)ms, and the amplitude was (-14.78±1.40)μV; the latency of the P3a component on the Pz lead was (317.21±5.65)ms, and the amplitude was (3.70±0.13)μV. Compared with normal children, the MMN of children with ADHD had smaller amplitudes in the Fz and Cz leads, and the P3a had greater latency and smaller amplitudes in the Cz and Pz leads ( t =2.79,2.20；-2.04，-3.25；2.35,3.21， P <0.05). Correlation analysis showed that the latency of MMN in children with ADHD was positively correlated with the inattention score in the SNAP-Ⅳ( r =0.22), and the amplitude of MMN was negatively correlated with the inattention score in the SNAP-Ⅳ and the learning problem score in PSQ ( r = -0.26 , -0.34)( P <0.05). The latency of P3a was positively correlated with the scores of inattention in the SNAP-Ⅳ and the score of learning problems in the PSQ ( r =0.26 ,0.24); the amplitude of P3a was negatively correlated with the scores of attention deficit and hyperactivity/impulsivity in the SNAP-Ⅳ and the scores of learning problems and impulsivity/hyperactivity in the PSQ( r = -0.26 , -0.22, -0.25,-0.32)( P <0.05). Conclusions School aged ADHD children exhibit abnormal MMN/P3a components, indicating attention related cognitive dysfunction. Symptoms such as inattention, learning problems and hyperactivity/impulsivity in children with ADHD are related to abnormal components of MMN and P3a.