This study aims to assess the prevalence of Autism Spectrum Disorder (ASD) and its treatment. The study population was children aged 3-17 years with information on current ASD from National Survey of Children's Health, 2016-2022. Analysis of treatment was also conducted within the population of children with a current ASD diagnosis. A multivariate log-binomial regression model was used to assess the change of current ASD prevalence and ASD treatment by two study period (prior to COVID-19 pandemic: 2016-2019; during COVID-19 pandemic: 2020-22) and sociodemographic information. Compared to the current ASD at 2.5% in 2016, it increased to 3.6% in 2022. The treatment has decreased from 70.5% in 2016 to 61.6% in 2022 for any treatment and from 27.2% in 2016 to 20.4% in 2022 for medication treatment. Compared to children from 2016-2019, children from the following group were more likely to have ASD diagnosis during the pandemic (2020-2022), including those aged 3-5 years (aPR = 1.66, 95%CI 1.29-2.13), non-Hispanic white children, children from family with above national family income, and those with private insurance. However, medication treatment almost halved during the pandemic for non-Hispanic black children (aPR = 0.49, 95%CI 0.26-0.93) and children born overseas. In conclusion, higher prevalence of ASD might indicate a better awareness of ASD. The reduction in treatment correlates to the health service disruption caused by the pandemic, highlighting the needs of policy efforts to improve treatment for ASD.