Background: Atopic dermatitis (AD) is one of the most prevalent chronic inflammatory skin disorders that causes great disease burdens world-wide. The demographics and clinical characteristics of AD are different between countries, regions, and age groups yet these differences were not well characterized in China. To get well guidance for AD clinicians, we described the demographics, clinical characteristics, comorbidities, patient-identified aggravating factors and treatment of AD in all-age patients in China. Methods: This study included Chinese individuals diagnosed with AD by accredited clinicians in the department of dermatology of 205 hospitals from 31/34 provincial administrative divisions across China during August, 2021 to September, 2022. All included patients completed dermatologist-lead interviews regarding their general medical history, comorbidities, AD-related aggravating factors and medications. Two-level mixed ordered logistic regression was used to evaluate factors for aggravation of the disease. Results: Overall, 16838 respondents were included in the final analysis with a mean age of 30.94 years (standard deviation, ± 24.08 years). The proportion of patients with severe AD was the highest in patients with onset of AD at ≥60 years old (26.73%). Allergic rhinitis and hypertension were the most common atopic and non-atopic comorbidities, respectively. AD severity was significantly associated with chronic urticaria, food allergy and diabetes. There was a high proportion of severe AD in patients who had aggravating factors such as seafood, lamb and beef, chili peppers, alcohol, seasonal changes, and psychological factors. Cross-sectional survey revealed unmet needs of severe AD in treatment strategy, in lack of immunosuppressants’ and biological agents’ application. Conclusion: Treatment of comorbidities and control of aggravating factors significantly contribute to AD management. Improving systemic immunotherapy could reduce the incidence of severe AD.