Lung cancer is the rapidest increased type of cancer in China with over 5 times incidence rate increase during the past 30 years . It is the leading cause of death of cancer in man and 2nd in women. With the development of gefitinib and erlotinib, EGFR-TKI (epidermal growth factor receptor -tyrosine kinase inhibitor) is the most successful novel drugs developed for the treatment of these patients in recent years, especially for NSCLC patients in Asia including China. Icotinib is a novel EGFR-TKI developed by a group of Chinese scientists and clinician. It appears to be at least as good as gefitinib in terms of efficacy and better in terms of safety in phase I/II trials. In this study, a randomized, double-blind, gefitinib as control, multi-center phase III trial was designed to evaluate the safety and efficacy of icotinib in the treatment of advanced NSCLC patients after failure of 1 or 2 chemotherapy. PFS (progress free survival) is the primary end-point with OS (overall survival), ORR (objective response), TTP (time to progress), HRQOL and safety as the secondary end-point. A total of 400 patients will be recruited. EGFR and K-ras gene mutational analysis as well as a population PK study have also been proposed.