Abstract： Objective To evaluate the efficacy and safety of 2 different doses of pirfenidone in the treatment of radiation-induced lung injury in patients with esophageal carcinoma.Methods 73 patients with esophageal cancer were randomly divided into 2 groups,41 patients in the 400mg group were treated with concurrent chemoradiotherapy combined with pirfendione 1200 mg/d,and 32 patients in the 200mg group were treated concurrent chemoradiotherapy combined with pirfendione 600 mg/d and placebo 6 pills/d.The patients were followed up for 1 year to compare the short-term therapeutic effect of tumor and the incidence of radiation-induced lung injury,the changes of lung function and serum levels of lung injury-related cytokines before and after ra-diotherapy,and the incidence of adverse reactions was compared between the 2 groups.Results The effective rate of 400 mg group was 90.2％,which was not significantly different from that of 200 mg group(84.4％,P＞0.05).The incidence of pulmona-ry fibrosis was 9.8％and 12.2％in 400mg group at 6 months and 1 year after radiotherapy,which were lower than 28.1％and 31.3％in 200mg group respectively(P＜0.05).Forced expiratory volume in 1 second(FEV1),forced vital capacity(FVC)and diffusion capacity of carbon monoxide(DLCO)were lower in both groups at 3,6 months and 1year after radiotherapy than those before radiotherapy,the levels of lung injury-related cytokines in 400mg group were higher than those in 200 mg group at the same time(P＜0.05),and the levels of lung injury-related cytokines in both groups were higher at 3 months after radiotherapy than those before radiotherapy,and decreased at 6 months and 1 year after radiotherapy,however,the incidence of adverse reactions in the 400 mg group was lower than that in the 200 mg group(P＜0.05),and there was no significant difference between the 2 group(P＞0.05).Conclusion The combination of higher dose pirfenidone(1200 mg/d)has better efficancy and better tolerance for radiation-induced lung injury in patients with esophageal carcinoma.