OBJECTIVE： To investigate the relationship of Cytochrome P450（CYP）3A4*18 gene polymorphism with therapeutic efficacy and ADR of epidermal growth factor receptor tyrosine kinase inhibitor （EGFR-TKI） in non-small cell lung cancer （NSCLC） patients receiving primary treatment. METHODS： A total of 46 advanced NSCLC patients receiving primary EGFR-TKI  （gefitinib or erlotinib） treatment until disease progression or intolerance were selected from our hospital during Jan. 2013-Mar. 2016， and （gefitinib of erlotinib） treatment until disease progression or intolerance. CYP3A4*18 genotype was detected by PCR and direct sequencing. Clinical efficacies， progression-free survival （PFS） and the occurrence of ADR were compared among different genotypes. RESULTS： Among 46 patients， there were 17 cases of CYP3A4*18 wild-type and 29 cases of CYP3A4*18 mutation-type， with mutation frequency of 63.0％. The objective response rate （ORR） of CYP3A4*18 wild-type patients was 23.5％， and disease control rate （DCR） of them was 70.6％. For CYP3A4*18 mutation-type patients， ORR and DCR were 27.6％ and 69.0％. There was no statistical significance in the proportion of patients with partial response， stable disease or progressive disease， ORR or DCR among different genotypes （P＞0.05）. PFS of female patients were significantly longer than male patients； those of patients without smoking history were significantly longer than those with smoking history， with statistical significance （P＜0.05）. There was no correlation between patients’age， therapy drugs， Eastern Oncology Collaboration scores， EGFR mutation types， CYP3A4*18 genotypes and PFS （P＞0.05）. Patients’gender and smoking history were independent prognostic factors for PFS [odds ratios were 3.438， 0.205， 95％ CI were（1.393，8.488），（0.088，0.481）]. Among CYP3A4*18 wild-type patients， 6 patients suffered from rash （35.3％） and 3 diarrhea （17.6％）. Among mutation-type patients， 26 patients suffered from rash （89.7％） and 15 diarrhea （51.7％）， with statistical significance （P＜0.05）. There was no statistical significance in the incidence of liver function injury and interstitial dermatitis among different genotypes （P＞0.05）. CONCLUSIONS： CYP3A4*18 gene polymorphism may be not associated with therapeutic efficacy of EGFR-TKI in advanced NSCLC patients receiving primary treatment， but it is correlated with the occurrence of ADR. Mutation type patients are more likely to suffered from rash， diarrhea and other ADR.