Objective To observe the difference of the dynamic changes and the degree of the fibrosis induced by two different methods that one-time-large-dose(OLD) of tail vein injection and multiple-low-dose (MLD) of tail vein injection of bleomycin ( BLM). Methods 126 male ICR mice with age of 8 wk were randomly divided into OLD model and MLD model.The OLD model was classified into three groups with the different dose 200mg/kg（ ML）, 150mg/kg（MM）,100mg/kg（MS）and negative control group ,and injiected with BLM200mg/kg、150mg/kg、100mg/kg and Saline 10ml/kg respectively. 6 mice were executed after injection in 7, 14 and 21days, respectively. The multiple low dose model was classified into 10mg/kg/d group (M)and negative control group . Six mice were executed after injection of BLM and Saline in 14, 21 and 28 days, respectively,each group was injectied 14 days continuously. The weigh ,survival rate , pathological changes and collagen III in the lung tissue were observed. Results ①In the OLD model, degree of alveolar inflammation score and lung fibrosis score of the mice in all groups were significantly higher than the normal group (P < 0.05) except the MS group and the MM group (p>0.05)executed in 7 days. The expression of Ⅲ collagen in all groups were significantly higher than the normal group (P<0.05) except the MS group (p>0.05)executed in 7 days. The expression of Ⅲ collagen in each group at 21 days reached a peak, and the 200mg/kg group executed in 21 days is the higest; the model mice in each dose group no deaths, the mortality rate was 0;②In the MLD model, compared to the normal group, the alveolar inflammation and pulmonary fibrosis of all the groups were statistically significant (P<0.05);the type III collagen expression of all the groups was also higher than normal (P<0.05) group, and the increase was progressive with time, peaked at 28 days; in this model , there are 11 mice died, the mortality rate was 30.56% .③The comparison between each group after injiection 14 days , The expression of Ⅲ collagen in pairwise comparisons between each groups were not statistically significant (P> 0.05) , except with 200 mg/kgBLM group and 10 mg/kg/dBLM groups compared to 100 mg/kgBLM group was statistical significance（P >0.05）, respectively. The comparison between each group after injiection 21 days , The expression of Ⅲ collagen in 200mg/kg BLM group higer than other groups (p<0.05),and the 100mg/kg BLM group lower than other groups ,and there is no significant differences between the the 150mg/kgBLM group group 10mg/kg/dBLM group (P> 0.05).conclusion In our experiments , the model of the injection BLM200mg/kg 21 days, is the most successful model , the mortality of mice is low, operation is simple and effective safety and convenience features to make it hopes to become a copy of the ideal model of pulmonary fibrosis.