Abstract: Objective To investigate the efficacy and side effect of icotinib hydrochloride in treatment of advanced nonsmall cell lung cancer（NSCLC）. Methods Fifteen patients with advanced NSCLC were treated with icotinib hydrochloride（125mg，tid，4 weeks／cycle）. The efficacy was evaluated by RECIST 1.1 every two cycles. The patients achieving CR，PR or SD continued the treatment with assessment once every two cycles until progression or intolerance. The improvement rates of symptoms and PS score，occurrence of side effects and drug resistance were investigated. Results One patient out of the total 15 patients died and 14 patients were evaluable for efficacy. One CR，5 PR，5 SD and 3 PD were observed after the first cycle with the response rate of 42.9％ and disease control rates of 78.6％.The symptom remission rate was 87.5％ with symptom remission time ranging from 3 hours to 14 days. The improvement rate of PS score was 45.4％. Rapid drug resistance occured in 4 patients（36.4%）. The main side effect observed was grade 1 leukopenia in 2 patients. Conclusion Icotinib hydrochloride in the treatment of advanced NSCLC may have good efficacy and less toxicity. However，a few patients got resistance in a short time，which is worth of discussion.