BackgroundAttention deficit hyperactivity disorder （ADHD） is a neurodevelopmental disorder characterized by age-inappropriate inattention， excessive activities incongruous with setting， and emotional impulsivity. Subthreshold ADHD （sADHD） is clinically defined as the presence of ADHD symptoms that do not meet the full diagnostic criteria for ADHD. Children with sADHD exhibit deficits in executive function， demonstrate more conduct， learning， and anxiety-related problems compared to typically developing children， and show even poorer working memory performance than children diagnosed with ADHD. Currently， there is limited epidemiological research on sADHD in China， with few studies simultaneously investigating the prevalence of both ADHD and sADHD in children. ObjectiveTo investigate the prevalence of ADHD and sADHD among children aged 6–13 years in Chongqing， analyzing their distribution characteristics within this population， with the aim of providing references for developing preventive measures against both ADHD and sADHD. MethodsFrom October to November 2023， a total of 3 398 students in grades 1–6 from six primary schools in Jiangbei District， Chongqing were selected using a stratified cluster random sampling method. The occurrence of ADHD and sADHD was evaluated by using the short version （18-item version） of the Swanson， Nolan， and Pelham IV rating scales （SNAP-IV） and the Chinese vision of Schedule for Affective Disorder and Schizophrenia for School-aged Children-Present and Lifetime Version （K-SADS-PL）. ResultsThe ADHD detection rate among children in Chongqing was 1.90% （95% CI： 0.014–0.024）. Boys showed a significantly higher ADHD detection rate than girls （χ²=7.733， P=0.005）. No statistically significant differences were found in ADHD detection rates across different grades or age groups （χ²=7.347， 12.362， P>0.05）. The sADHD detection rate was 6.32% （95% CI： 0.054–0.072）. Similarly， boys exhibited significantly higher sADHD detection rates than girls （χ²=21.005， P<0.01）. Significant differences emerged across different grades （χ²=20.559， P=0.001）， while no statistically significant difference was observed in age groups （χ²=12.070， P=0.060）. ConclusionThe ADHD detection rates were comparable across all grade levels and age groups from 6–13 years old. Second-grade children demonstrated notably higher sADHD rates compared to other grades， while boys demonstrated higher prevalence rates than girls for both ADHD and sADHD. ［Funded by Science and Health Joint Medical Research Project in Jiangbei District， Chongqing City in the Second Half of 2023 （number， 2023JBKWLH022）］