Objective To study the characteristics of quantitative EEG in epilepsy patients after ischemic stroke.Methods Sixty-seven first-ever epilepsy patients after ischemic stroke served as an observation group and 74 age-matched healthy persons served as a control group in this study.The quantitative EEG power spectra of two groups,including δ (0.8-3.9 Hz),θ (4.0-7.7 Hz),α (7.8-12.9 Hz) and β (13.0-20.0 Hz),were analyzed using the Z2N-F32w EEG device made in Shanghai.The (δ+θ)/(α+β) power value on different regions of brain between the two groups was computerized and used as an observation index.Results The ischemic stroke size was not related with the (δ+θ)/(α+β) power value in observation group (P＞0.05).The (δ+θ)/(α+β)power value on the left frontal area (3.15±2.63 vs 1.97±1.42,P=0.002),right frontal area (3.17±2.53 vs 1.88±1.46,P=0.000),left central area (2.69±2.59 vs 1.65±1.28,P=0.004),left parietal area (2.58±2.45 vs 1.28±1.10,P=0.000),right parietal area (2.69±2.81 vs 1.21± 1.06,P=0.000),left occipital area,right occipital area,left temporal area and right temporal area was significantly higher in observation group than in control group (P＜0.01).No significant difference was found in (δ+θ)/(α+β) power value on the right central lobe and left occipital lobe between the two groups and between early and late onset epilepsy patients after ischemic stroke (P＞0.05).Conclusion Quantitative EEG plays an important role both in diagnosis of epilepsy and in assessment of abnormal brain electrical activity in epilepsy patients after ischemic stroke.