Abstract： Objective To analyze the low dose-volume associated with radiation-induced lung injury (RILI) in patients with advanced non-small cell lung cancer (NSCLC) treated by three-dimensional confor-real radiation therapy (3DCRT). Methods Data of 100 patients with histologically proved NSCLC treated with 3DCRT or IMRT between November 2006 and January 2009 were collected. Nine patients treated with radiotherapy alone and 91 with radiotherapy combined with chemotherapy. A median dose of 70 Gy (range,60-80 Gy) was delivered with late-course accelerated hyperfractionated radiotherapy (LAHRT). Twenty-four patients received dose of 61-69 Gy and 76 received more than 70 Gy. The V_5 ,V_(10) ,V_(20) ,V_(30)and mean lung dose (MLD) were calculated from the dose volume histogram system. The RILI was evaluated according to Common Toxicity Criteria 3.0(CTC 3.0). Results The range of V_5 ,V_(10) ,V_(20) ,V_(30) was 37%-98%,27%-78%, 17%-54% and 9%-31%, respectively, with a median value of 65%, 47.5%, 31% and 24%, respectively. The acute RILI of grade 1, 2, 3, 4 and 5 was observed in 34, 27, 8, 1 and 1 patients,respectively. The chronic RILI of grade 1, 2 and 3 was observed in 46, 14 and 2 patients, respectively. V_5 ,V_(10) ,V_(20) and MLD were significantly correlated with acute RILI of ≥ grade 1. V_5 ,V_(20) ,V_(30) and MLD were significantly correlated with acute RILI of ≥ grade 2. The acute RILI of ≥ grade 2 was significantly in-creased when V_5, V_(20) and V_(30) were more than 65%, 31% and 24%, respectively. The acute RILI of ≥ grade 3 was significantly increased when V_5 was more than 65%. The acute RILI of ≥ grade 1 was signifi-candy increased when V_(20)was more than 31%. The gross tumor volume and planning target volume were sig-nificantly correlated with the acute RILI of ≥ grade 1 and chronic RILI of ≥ grade 2. Conclusions The dose-volume V_5 and V_(10) are effective in predicting RILI.