Objective:To evaluate the effects of topiramate(TPM) and sodium valproate retard tablet(VAP) on cognitive function in adult patients with epilepsy. Methods:Sixty-two adult patients,newly diagnosed as epilepsy,were randomly divided into 2 groups:TPM Group(n = 30) and VAP Group(n = 32). The cognitive function of all the patients in these two groups were evaluated by the Revised Adult Wechsler memory scale(WMS-RC) and event related potentials(ERPs) before treatment and after two months administration of TPM/VAP. Results:①Before administration of TPM:Memory Quotient(MQ) < 100,accounting for 26.67%;In the ERPs,the P3 wave latency >359.9ms,accounting for 33.33%. Before administration of VAP:MQ < 100,accounting for 28.0%;In the ERPs,the P3 wave latency > 359.9ms,accounting for 31.25%. There was not significant difference between these two groups with respect to the cognitive function(P > 0.05). ②After administration of TPM,in TPM Group the score of sequence counts of 1 to 100 declined(P < 0.01),the score of sequence counts of 100 to1 declined(P < 0.05), the score of digit cumulate cognitive function declined(P < 0.05),the mistakes of cards recognition increased(P < 0.01), the function of cards remembrance declined(P <0.01), the mistakes of cards reclamation increased(P < 0.01),the mistakes of word association increased(P < 0.01), the object touch was more difficult(P < 0.01), the function of story apprehension declined(P < 0.01)and the natural order and anti- natural order repeat of digit were more difficult(P < 0.01). In the ERPs, the N1 wave latency prolonged(P < 0.05) and the P2,N2 and P3 waves latencies all prolonged significantly(P < 0.01),while the amplitude of P3 wave declined(P < 0.01). After administration of VAP,in VAP Group:the score of WMS-RC TEST in every item did not change significantly(P > 0.05). In the ERPs,the N1 wave latency shortened(P < 0.05) and the P2,N2 and P3 waves latencies all shortened significantly(P < 0.01),while the amplitude of P3 wave did not increase significantly(P > 0.05). ③The transient memory of WMS-RC was reversely correlated with the P3 wave latency(P < 0.05). Conclusion:After administrateration of TPM,patients with epilepsy who were in the drug titration phase were more likely to suffer from many cognitive disturbers;Patients’ cognitions were improved by administration of VAP;After examination of ERPs and WMS-RC ,the results of evaluation of cognitive function will be more objective and comprehensive.