Objective:Observation of bleomycin (BLM) induced rat model of pulmonary fibrosis lung tissue at different time points dynamic evolution process.Methods:Used intratracheal instillation of bleomycin-induced pulmonary fibrosis Wistar rat model,Observed the evolution of different time points of lung by HE,MASSON.Results:With the extension of time,alveolitis,fibrosis,and collagen deposition increasing.Conclusion:Bleomycin (BLM) induced rat model of pulmonary fibrosis lung tissue with dynamic phase of evolution.