Objective To explore the possibility of applying SARS-CoV infected animal model to clarify the pathogenesis of pulmonary fibrosis(PF) in SARS.Methods We compared the difference and similarity of SARS features and pathogenesis between SARS patients and SARS animal model emphasized on PF.Results Beginning from alveolitis,PF in different diseases has similar pathological changes in a progressive and reparative process.About 7-8% of SARS convalescent patients showed apparent PF,which affected their life quality and increased medical treatment costs.PF in SARS patients appears in the early stage and develops very fast.These patients died within a few days with severe pathological changes in many organs,especially in the lungs.SARS-CoV infected animal model had been established,which showed similar clinical,serological and pathological changes to those in SARS patients.In these animals,PF is also apparent with increased amount of fibroblasts and collagen.Conclusions SARS-CoV infected animal models are useful in studies on pathogenesis of pulmonary fibrosis in SARS patients.