Objective　To investigate whether the isoform-specific influence of apolipoprotein E gene(APOE) on the electrical activity of brain is induced by traumatic brain injury (TBI). 　Methods　The clinical data of 118 patients with mild/moderate traumatic brain injury and 40 normal subjects for control were collected

and the APOE genotyping was performed by means of PCR-RFLP. The electrical activity of brain in every patient was recorded by electroencephalogramy within 3 d after injury and all the subjects for control were examined by electroencephalogramy under conscious，calm

eyes-closed and normoglycemic condition. Quantitative data of every electroencephalogram were collected. 　Results　The quantitative data among APOEε2

APOEε3 and APOEε4 groups of normal subjects had no statistic difference (P=0.097). In 118 patients with mild/moderate TBI

the quantitative data among APOEε2

APOEε3 and APOEε4 groups had significant difference (P=0.008). Compared with APOEε3 group

the energy value of slow waves was more in the APOEε4 group and less in APOEε2 group. 　Conclusion　In normal adults

the electrical activity of brain is not significantly different among the three APOE groups. However

under the provocation of traumatic brain injury

the electrical activity of brain in the three groups shows different. After traumatic brain injury

APOEε4 is bad for the electrical activity of brain but APOEε2 protects brain function.