Objective:To investigate the correlation between ATP-binding cassette B subfamily 1 transporter(ABCB1)gene polymorphism and the efficacy of levetiracetam(LEV)in children with epilepsy.Methods;A total of 94 children with epilepsy were se-lected as the research subjects.According to the curative effect,they were divided into effective group(n=76)and ineffective group(n=18).Polymerase chain reaction and fluorescence in situ hybridization(PCR-FISH)were used to detect ABCBI genotypes in all children,and clinical data were collected.The clinical data and ABCBI genotype were compared between the two groups.Logistic regres-sion model was used to determine the risk factors of LEV treatment failure.Results;Compared with the effective group,the proportion of first onset as myoclonic type,seizure frequency,EEG abnormality and birth suffocation in the ineffective group were higher(P＜0.05).Compared with the effective group,the proportion of ABCB1 C3435 T TT type in the ineffective group was higher,and the frequency of T gene distribution was higher,the differences were statistically significant(P＜0.05).Logistic regression analysis showed that seizure frequency(OR=5.812),birth asphyxia(OR=3.274),and ABCB1 genotype(OR=7.675)were independent influencing factors of LEV efficacy in children with epilepsy(P＜0.05).The risk of treatment failure with TT genotype was higher than that with CC and CT genotypes.Conclusion:ABCB1 gene polymorphism is closely related to the efficacy of epilepsy in children.TT genotype may be a risk factor for LEV treatment failure.In addition,the risk of ineffective LEV treatment is higher in patients with higher seizure frequency and birth asphyxia.