AIM: To observe the effects of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), myeloperoxidase (MPO) and transforming growth factor-β1 (TGF-β1) of radiation-induced lung injury rats by Kiwi fruit essence (unsaturated fatty acid of actinidia chinesis planch seed oil). METHODS: According to random number table, 90 Sprague-Dawley rats were divided into the control group, model group, 60 mg/kg unsaturated fatty acid of actinidia chinesis planch seed oil intervention group, 120 mg/kg unsaturated fatty acid of actinidia chinesis planch seed oil intervention group, 240 mg/kg unsaturated fatty acid of actinidia chinesis planch seed oil intervention group, 18 animals were included in each group. Except for the control group, rats in the remaining groups were constructed by 6MV-X-ray 18Gy full chest radiation, one week before modeling, the rats in the last 3 groups were given (60, 120, 240) mg/kg unsaturated fatty acid of actinidia chinesis planch seed oil. The first two groups were given 0.9% sodium chloride solution by gavage, once a day in each rat. 14 days, 28 days, and 56 days after radiation, the rats were randomly sacrificed and their chests were cut, and ave lung tissue was saved. HE and Masson staining were performed to observe the pathological changes, and the content of SOD, GSH-Px, MPO was determined. The expression of TGF-β1 was analyzed by immunohistochemical staining. RESULTS: Compared with the model group, (60, 120, 240) mg/kg unsaturated fatty acid of actinidia chinesis planch seed oil significantly reduced the degree of lung alveolitis and radiation pulmonary fibrosis, reduced the content of hydroxyproline (HYP), MPO, increased the antioxidant enzymes SOD and GSH-Px content, down-regulated the expression of TGF-β1.There were significant differences in the above-mentioned indicators among the intervention groups of (60, 120, 240) mg/kg unsaturated fatty acid of actinidia chinesis planch seed oil group, and it was positively correlated with dosage. CONCLUSION: Unsaturated fatty acid of actinidia chinesis planch seed oil has a preventive effect on radiation-induced lung injury, and its mechanism may be related to the reduction of oxidative stress damage and down-regulation of TGF-β1 expression.