Abstract: Objective To observe and analyze the curative effects of the combined sequential application of erlotinib between the chemotherapy periods in the treatment of the patients with ad-vanced non small cell lung cancer (NSCLC).Methods 45 patients with advanced NSCLC were se-lected as the research objects.The patients of the initial treatment were treated with gemcitabine combined with platinum for chemotherapy and the patients of retreatment were treated with doc-etaxel or pemetrexed for chemotherapy.Between the chemotherapy periods,the sequential erlotinib therapy was applied to all the patients.The short-term curative effects and the adverse reactions were evaluated and compared.Results The clinical efficiency of the initial treatment patients and the retreatment patients were 27.6% and 18.8% respectively.There were no significant differences of short-term curative effects and the clinical efficiency between the initial treatment patients and the retreatment patients (P >0.05),while the clinical control rate of the initial treatment patients was significantly higher than that of the retreatment patients (P <0.05).The clinical efficiency of the patients with a smoking history was significantly lower than that of the patients without smok-ing history(P <0.05).The clinical efficiency of the initial treatment patients with age of 65 years or older was significantly higher than that of the initial treatment patients of age < 6 5 years (P <0.05).The clinical efficiency of the initial treatment patients with stage Ⅲb was signifi-cantly higher than that of the initial treatment patients with stage Ⅳ(P <0.05).The clinical ef-ficiency of the retreatment patients with adenocarcinoma pathological type was significantly higher than that of the patients without adenocarcinoma pathological type (P <0.05).The main adverse reactions of the patients were nausea,diarrhea,rash,vomiting,loss of appetite.Conclusion The clinical efficiency of the combined sequential application of erlotinib between the chemothera-py periods in the treatment of the patients with advanced NSCLC is not high.Smoking history, age,tumor stage,pathological type may affect its curative effect.The effects of this therapy in controlling the disease progress of the initial treatment patients are more significant,the adverse reactions are mild,and the tolerance of the patients for the therapy is higher.