Objective A rat model of pulmonary fibrosis was constructed using single or two intratracheal drops of bleomycin (BLM) to compare the modeling rate and stability of the two modeling modalities. Methods A total of 150 SPF-grade SD rats were randomly divided into blank control group (Control group), single intratracheal drop of bleomycin (BLM-S group) and two intratracheal drops of bleomycin (BLM-M group). BLM (3 mg/kg, single time) was given by noninvasive intratracheal instillation in the BLM-S group. The rats in BLM-M group were intratracheal instilled with BLM (3 mg/kg, 2 mg/kg) on day 1 and day 14, and those in Control group were given intratracheal instillation of 0.9% sodium chloride injection (1 ml/kg). These rats were put to death in batches on the 28th, 42nd, 56th and 84th day after modelling. All of the rats were used to measure deep inspiratory capacity (IC), vital capacity (VC), static lung compliance (Cchord), and dynamic lung complication (Cdyn); The pathological changes of lung tissue were observed, and the extent of alveolitis and fibrosis was graded. Additionally, the expression of collagen-III (COL-III) in rat lung tissue was detected by immunohistochemistry. Results (1) General condition and survival: Respectively, The survival rates of Control, BLM-S and BLM-M groups were 100%, 80% and 66%. Rats in the BLM-S and BLM-M groups had substantially reduced body weights on days 14 to 42 compared to the Control group (P < 0.05, P < 0.01). Rats in the BLM-M group had substantially less body weight on days 28-42 than those in the Control and BLM-S groups (P < 0.05, P < 0.01). (2) Lung function: compared with the Control group, IC, VC, Cchord, and Cdyn were markedly decreased in the BLM-S group ( P < 0 .05, P < 0 .01) and IC, VC, and Cchord were significantly decreased in the BLM-M group ( P < 0 .05, P < 0 .01) on day 28; rats in the BLM-S group on day 42 had IC, VC, Cchord decreased significantly ( P < 0 .05, P < 0 .01); IC, VC, and Cchord decreased significantly ( P < 0 .05, P < 0 .01) in rats in the BLM-M group on days 42 to 84. (3) Lung pathology: inflammatory infiltration and fibrous cords appeared in BLM-S group from day 28 to 84, and then gradually decreased (P< 0.05, P< 0.01). In the BLM-M group, the fibrosis and alveolitis were relatively stable (P< 0.05, P< 0.01). (4) Collagen deposition: at all time points, the expression of COL-III in the lung tissue of rats in the BLM-S and BLM-M groups was significantly higher than that in the Control group (P < 0.05, P < 0.01); The content of COL-III in BLM-S group at 42-84 days was significantly lower than that at 28 days (P < 0.05). Conclusion Both methods are capable of effectively creating pulmonary fibrosis models. The single-dose approach is straightforward and has a reduced death rate, and the degree of fibrosis is clearly visible, in the 28 day, however, after 42 days, it progressively recovers. The two-time method instillation modeling has a greater success rate and better stability. Even, On the 84th day, over half of the rats still exhibited visible fibrosis.