Objective To investigate the value of combined detection of video electroencephalography（VEEG） and MRI in early diagnosis of adult viral encephalitis (VE). Methods Clinical data of 128 patients with VE in our hospital from January 2015 to January 2018 were analyzed retrospectively, and the results of MRI and VEEG were also analyzed. Results The VEEG had higher severe abnormal rate and lower normal rate than those of the MRI (P<0.05), while no difference was found in the mild to moderate abnormal rate (P>0.05). The MRI results showed that the lesions of 128 patients were mostly involved in the medial and frontal lobes of the temporal lobe, and a few were involved in the insula. Single affected organs included 15 cases (17.86%) of frontal lobe, 10 cases (7.82%) of parietal lobe, 15 cases (17.86%) of temporal lobe, 21 cases (16.41%) of insular lobe, 13 cases (15.48%) of basal ganglia lobe, 7 cases (5.47%) of brain stem, and 3 cases (3.57%) of cerebellum. Double affected organs included 31 cases (24.22%), and 13 cases (10.16%) had more than three lesions involved. Most of the lesions were bilateral, multiple, cortica,, and both cortex and white matter could be involved, which was commonly seen in the cortex matter. The signals showed low signal on T1WI and high signal on T2WI. The lesions were better displayed in FLAIR sequence than T1WI and T2WI imaging, of which 14 (10.93%) had normal signals in T2WI while presented as high signal by FLAIR. Both T1WI and T2WI had high signals during hemorrhage, and enhanced scans varied greatly, including no significant enhancement, line-like enhancement, brain-like enhancement, and minor meningeal enhancement. Conclusion Combination of VEEG and MRI has a high detection value for adult VE, which can clarify the disease severity and lesions involvement with higher detection rate.