Objective To explore the effect of brain-derived neurotrophic factor (BDNF) Val66Met polymorphism,environmental factor and their interactions on antidepressant treatment.Methods 340 patients of major depressive disorder (MDD) who met the diagnosis criteria of MDD ( DSM-Ⅳ Axis Ⅰ) were recruited.280 patients of them were finished 12 weeks antidepressant treatment.The severity of depression was measured with the Hamilton Depression Rating Scale (HDRS) before and after 12 weeks antidepressant treatment.Childhood Trauma Questionnaire,28-item Short Form (CTQ-SF) and Life Events Scale (LES) were used to evaluate childhood adverse and life stress before onset.Genotyping of BDNF Val66Met polymorphism was detected by Illumina GoldenGate assays.Results Male patients proportion were significantly higher in non-remitters than remitters (P =0.008 ).After adjusting by gender, the frequencies of genotype and allele for the BDNF Val66Met polymorphism were no significant difference between remitters (AA: AG: GG = 28: 79: 40, A:G = 135:159 ) and non-remitters (AA: AG: GG = 29:81:23 ,A: G = 139:127 ) (P ＞0.05 ).There was no significant difference of CTQ scores and LES scores between the two groups (P＞0.05 ).The regression analysis showed that social intercourse problem and age were the risk factor for the severity of depression.The gender, HDRS baseline scores and mental disorder family history were associated with the efficacy of 12 weeks antidepressant.However,there was no significantly relationship between the interaction of BDNF Val66Met polymorphism and environment with the antidepressant treatment.Conclusion The older men with the mental disorder family history, severe depression symptom would be less-response to antidepressant treatment.However, BDNF Val66Met polymorphism, childhood trauma, life events stress and the interaction of BDNF Val66Met polymorphism and environment have no significantly effect on the 12 weeks antidepressant treatment.