Objective To observe the preventive effect of Anduolin(ADL) on radiation-induced lung injury in mice.Methods Totally 180 of Kunming mice were randomly classified into six groups:normal control group ( N ),irradiation control group ( R),irradiation plus low dose ADL group ( L),irradiation plus middle dose ADL group ( M),irradiation plus high dose ADL group ( H),and irradiation plus Dexamethasone group (D).The mice except group N were irradiated with 20 Gy of 6 MV X-rays on whole lung.The mice in group L,M and H were given with ADL 1 d before irradiation and continued for 6 weeks after irradiation.At 2,4 and 6 weeks after irradiation,the general situation and the lung pathological changes of mice were observed.The lung wet weight,collagen contents of the whole lung tissue,hydroxproline concentration,and TGF-β1 expression in the lung were also delected.Results Compared to the group R,the mice breathing rate,hydroxproline concentration,and TGF-β1 expression in the group L were not significantly changed.While in the groups M,H and D,the breathing rate,the generation of hydroxproline and the expression of TGF-β1 were decreased significantly ( F =2.668-161.646,P ＜0.05).In addition,ADL alleviated the pathological changes on radiation-induced lung injury in mice.Conclusions ADL might have the preventive effect on radiation-induced lung injury in mice.