The absence of a gold standard for treating pulmonary fibrosis makes its management challenging. We established a rat model to study the effect of resveratrol (Res) on bleomycin-induced pulmonary fibrosis. Rats were randomly divided into control, model, low-Res, middle-Res, high-Res, and dexamethasone groups and treated with various concentrations of these drugs. Rats showed typical features of pulmonary fibrosis; i.e., alveolitis, fibrous hyperplasia, and fibrosis on days 7, 14, and 28, respectively. Expression of HIF-1α and NF-κB was higher in the middle-Res, high-Res, and dexamethasone groups than in the control group, but was less than that in the model and low Res groups. We conclude that different levels of HIF-1α and NF-κB expression at different stages of pulmonary fibrosis in rats is positively correlated with the disease severity. Furthermore, resveratrol alleviates bleomycin-induced pulmonary fibrosis by suppressing HIF-1α and NF-κB expression, indicating its potential as a promising therapeutic drug candidate.