ObjectiveTo study the cognitive function and observe the changes of event-related potential of epileptic children.Methods45 epileptic children and 45 normal children were put in as the test group and the control group.The cognitive function and event-related potential were evaluated by means of Raven's standard Progressive Matrices (SPM) and evoked potential instrument respectively.ResultsAbout 33.3% epileptic children presented cognitive deficits.For children with cognitive deficits, their scores of B, E were significantly different from those in the control group(P0.05).The latency of event-related potential P300 showed significantly prolonged than that of the control group (P0.01).ConclusionEpilepsy may cause cognitive function deficit, especially in the ability of analog, analysis and abstract. The latency of event-related potential P300 is a very good objective to assess the cognitive function of children.