This phase II randomised, double blind, placebo controlled, multicentre trial is designed to assess the efficacy and safety of continuous icotinib plus chemotherapy versus chemotherapy alone in patients who have progressed after benefiting from previous second or third-line icotinib treatment (more than 6 months) in locally advanced or metastatic non-small cell lung cancer.

Inclusion Criteria:

• Histologically or cytologically confirmed stage IIIB/IV lung cancer(exclude patients confirmed by sputum cytology)
• No previous targeted treatment such as gefitinib, erlotinib.
• With a measurable disease(longest diameters >=10mm with Spiral computed tomography (CT)and >=20mm with conventional CT) according to RECIST Criteria
• WHO performance status(PS)<= 2
• N>=1.5×109/L, Plt>=1.0×109/L,Hb>=10g/dL;AST&ALT should <3ULN(without liver metastasis) or <5ULN(with liver metastasis).TBIL<=1.5ULN.
• Signed and dated informed consent before the start of specific protocol procedures.

Exclusion Criteria:

• Allergic to icotinib
• Patients with metastatic brain tumors with symptoms.
• Experience of Anti-EGFR(the epidermal growth factor receptor) Monoclonal Antibody or small molecular compounds therapy such as gefitinib, erlotinib or Cetuximab.
• Severe systemic disease out of control such as unstable or uncompensated respiratory,cardiac,liver,renal diseases.