The aim of present study was to evaluate the effects of the pilose antler peptide (PAP) on bleomycin (BLM)-induced lung fibrosis. The lung wet-to-dry weight (W/D) ratio and myeloperoxidase (MPO) activity were measured. The serum levels of super-oxide dismutase (SOD), malondialdehyde (MDA) were examined. Then the contents of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 were determined using ELISA method. Furthermore, the protein expressions of Rho, ROCK1, p-IκB, IκB, p-NF-κB, NF-κB in lung tissues were detected by western blot analysis. As a result, PAP markedly decreased pulmonary W/D ratio, lung MPO activity and relieved lung histopathological changes. In addition, PAP increased the level of SOD and reduced the levels of MDA, TNF-α, IL-1β, IL-6 in serum of BLM-stimulated mice. In addition, PAP remarkably inhibited the protein levels of ROCK/NF-κB pathway. In conclusion, our results showed that PAP exhibited protective effects on pulmonary fibrosis via the regulation of ROCK/NF-κB pathway.