Atopic dermatitis (AD) has the highest disease burden among all skin diseases. However, reports on AD prevalence trends in China are limited. This study aimed to investigate the time trends of AD prevalence in China from 1990 to 2021 and to explore the age and sex differences. Data were obtained from the Global Burden of Disease Study, 2021. We analyzed the annual percentage change in the crude prevalence rate and age-standardized prevalence rate (ASPR) of AD from 1990 to 2021 using the Joinpoint model. We predicted the future prevalence of AD from 2022 to 2030 using the Bayesian age-period-cohort model. The total ASPR decreased slightly from 1990 (1357.93 per 100,000) to 2021 (1347.11 per 100,000). The ASPR of females (1457.64 per 100,000) was higher than that of males (1247.04 per 100,000) in 2021. The prevalence rate of AD was highest in the under 5 years old age group (3455.56 per 100,000) and the 5-9 years old age group (3360.31 per 100,000). By 2030, the predicted ASPR of AD will be 1394.36 (per 100,000) in males and 1603.69 in females (per 100,000). The predicted prevalence rate in the under 5 years old (3996.14 per 100,000 in males and 3990.68 per 100,000 in females) and 5-9 years old (3714.61 per 100,000 in males and 3963.96 per 100,000 in females) age groups will be higher than those in other age groups. Despite a slight decrease from 1990 to 2021, there has been an increasing trend since 2015 in the total AD burden. Given the increasing burden of AD on Chinese children and females, healthcare practitioners should enhance community education, improve disease management abilities of patients and caregivers, and reduce the burden and healthcare costs of AD.