Objective: To compare the success rate and stability of rat pulmonary fibrosis (PF) models induced by intratracheal instillation of different doses of bleomycin (BLM). Methods: 150 SD rats were randomly divided into control group, low-dose BLM 3 mg/kg group (BL-L group), and high-dose BLM 5 mg/kg group (BL-H group). The general status, mortality, and weight changes of the rats were observed, the inspiratory capacity (IC), vital capacity (VC), chord compliance (Cchord) and dynamic compliance (Cdyn) of the lungs were detected on the 28th, 42nd, 56th and 84th days. Lung coefficients were recorded, pathological changes in lung tissue were observed by HE and MASSON staining, and collagen type III (COL III) expression in lung tissue was detected by immunohistochemistry. Results: (1) Mortality rate: The mortality rates of BL-L group and BL-H group were 20% and 28%. (2) Weight: The weight of the BL-L group was lower than that of the control group on days 0-56, and the weight loss was most significant on day 14 (P < 0.01), with weight recovery after day 56. From day 0 to day 56, the weight of the BL-H group was significantly lower than that of the control group and BL-L group (P < 0.01), and the weight gain remained relatively slow after day 56. (3) Lung function: compared with the control group, on day 28, the lung function of IC, VC, Cchord, and Cdyn were significantly lower in the BL-L group (P < 0.01, P < 0.05), and IC and Cdyn were significantly lower in the BL-H group (P < 0.01). On day 42, IC, VC, and Cchord decreased significantly in the BL-L group (P < 0.01, P < 0.05), while IC, VC, Cchord, and Cdyn significantly decreased in the BL-H group (P < 0.01, P < 0.05), and IC, VC, and Cchord were significantly lower compared with those in the BL-L group (P < 0.01). On day 56, Cchord was significantly lower in the BL-H group than in the control and BL-L groups (P < 0.01), and on day 84, there was no significant difference in lung function between the groups. (4) Lung coefficient: on day 28, the lung coefficients of the BL-L and BL-H groups were significantly higher than those of the control group (P < 0.01), and from day 42 to 56, the lung coefficients of the BL-H group were significantly higher than those of the BL-L group and the control group (P < 0.01), and on day 84, the lung coefficients of the groups did not differ significantly from those of the control group. (5) Lung histopathology and immunohistochemistry: inflammatory infiltration, fibrotic streaks and COL III expression were observed in the BL-L group from day 28 to 56, with the severity of the lesions decreasing over time, and the fibrotic lesions had almost disappeared on day 84, while in the BL-H group, significant fibrotic lesions could be observed from day 28 to 84, and the degree of COL III expression was significantly higher than that in the control group (P < 0.01). Conclusions: Both 3 mg/kg and 5 mg/kg BLM can successfully induce PF rat models. The PF model prepared with 3 mg/kg BLM developed fibrosis on day 28, which lasted until day 42 and gradually recovered. The PF model prepared with 5 mg/kg BLM showed fibrosis formation on day 28, and the degree of fibrosis was more severe than in the lower dose, with fibrotic lesions persisting stably up to day 56, and moderate-to-severe fibrosis still present in half of the cases until day 84.