OBJECTIVE： To explore the association between CYP3A4 gene polymorphism and the sensitivity of advanced gastric cancer patients to paclitaxel chemotherapy. METHODS： 67 patients diagnosed as advanced gastric cancer were selected from the Third Affiliated Hospital of Kunming Medical University during Mar.-Sep. 2014. Blood samples were collected before chemotherapy， and PCR-RFLP analysis was performed to detect CYP3A4 gene polymorphism. All patients were given two-drug chemotherapy based on paclitaxel. Therapeutic efficacy was evaluated by solid tumor therapeutic efficacy evaluation criteria， and objective remission rate （ORR） was used to evaluate chemotherapy sensitivity； the association between different genotypes and chemotherapy sensitivity was analysed. RESULTS： ORR of 67 patients with advanced gastric cancer was 38.8％； CYP3A4*2（+）， CYP3A4*3（+）， and CYP3A4*4（+） genotype patients accounted for 23.9％， 28.4％， and 26.9％ respectively. ORR of patients with CYP3A4*3（+）and CPY3A4*3（－）genotype were 57.9％ and 31.3％， with statistical significance （P＝0.044）； this genotype was associated with chemotherapy sensitivity [OR＝3.731， 95％CI（0.901，15.897）]. ORR of patients with CYP3A4*2（+）and CYP3A4*2（－）genotype were 43.7％ and 37.3％， without statistical significance （P＝0.642）； this genotype was not associated with chemotherapy sensitivity [OR＝1.075， 95％CI（0.274，16.289）]. ORR of patients with CYP3A4*4（+）and CYP3A4*4（－）were 33.3％ and 40.8％， without statistical significance （P＝0.577）； this genotype was not associated with chemotherapy sensitivity [OR＝0.938， 95％CI（0.735，14.732）]. CONCLUSIONS： CYP3A4*3 gene polymorphism may become a biomarker for predicting the sensitivity in advance gastric cancer patients to paclitaxel chemotherapy.