To investigate the role of TGF-β1 on the early lung remodeling after radiation pulmonary injury. The dose-effect of human lung fibroblast proliferation promoted by serum after radiated rat was observed by MTT colorimetric methods. ELISA was used to observe the contents of TGF-β1 in serum as well as the expression of collagen IV and MMP-9 in HLF stimulated by serum after radiated rat. The level of TGF-β1 in rat serum increased from 2 to 4 weeks after irradiation. HLF proliferation was significantly promoted by the serum of irradiated rat at a dose of 10% in the medium. The serum of irradiated rat could not only promote HLF proliferation, but also increase the expressions of collagen IV and MMP-9 in HLF. TGF-β1 plays an important role in the proliferation of HLF and the expressions of collagen IV and MMP-9 in HLF, and is involved in the process of lung remodeling after radiation pulmonary injury.