Objective:To analyze the clinical characteristics of patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).Methods:A retrospective study was conducted on AAV patients with long-term follow-up in the rheumatology outpatient clinic of Peking Union Medical College Hospital between February 2015 and February 2022. The demographic characteristics, clinical manifestations, concurrent events, treatment, and prognosis of the three clinical subtypes of AAV were collected and analyzed.Results:There were 71, 45, and 31 cases of granulomatous polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatous polyangiitis (EGPA), respectively, among 147 patients. The ANCA positivity rates in the three groups were 91.5%, 95.6%, and 19.4% ( χ2=76.68, P<0.01), respectively. The upper respiratory tract and lungs were the most frequently affected organs in GPA and EGPA, and the kidneys and lower respiratory tract were the main organs involved in MPA. In addition, cardiac and neurological involvement and thrombosis rates were significantly higher in EGPA patients than in GPA and MPA (12.9%, 9.7%, 41.9% and 19.4%, respectively; χ2=8.51、7.13、7.54、0.02, P<0.05) .The median follow-up time for the three groups of patients was 43, 28, and 46 months respectively.Relapse was more common in patients with GPA and EGPA (up to 59.2% and 64.5%; χ2=11.26, P=0.004), with the lungs and ENT being the most common relapse organs (GPA of 61.9% and 40.5%, EGPA of 55.0% and 50.0%), the lungs and kidneys were the most common manifestations in MPA relapse (64.3% and 60.0%, respectively). The main therapeutic agents were glucocortoid (95.9%), cyclophosphamide (71.4%), methotrexate (54.4%), tripterygium wilfordiz (34.0%),mycophenolate mofetil (31.3%), azathioprine (29.3%), leflunomide (19.0%), rituximab (19.0%), and tacrolimus/cyclosporine (8.8%). There were 6 deaths (4.1%) occurred during the follow-up period of this study. Conclusion:The clinical features of AAV are similar to those reported in the literature and relapses are common>he vast majority of patients need to be treated with glucocorticoid combined with immunosuppressive agents.