Objective By comparing the overlap syndrome of anti myelin oligodendroglia glycoprotein （MOG） antibody associated disease （MOGAD） and anti N-methyl-D-aspartate receptor encephalitis （MNOS） with MOGAD the clinical characteristics and differences of N-methyl-D-aspartate receptor encephalitis （NMDARe） in order to improve the understanding of MNOS.Methods A retrospective collection of 14 MNOS patients （MNOS group）， as well as 14 age and gender matched MOGAD （MOGAD group） and NMDARe （NMDARe group） cases each， was conducted to compare the clinical manifestations， cerebrospinal fluid examination， electroencephalogram， magnetic resonance imaging （MRI）， treatment， and prognosis of the three groups of patients.Results There was a significant difference in the proportion of consciousness disorders and optic neuritis among the three groups （P<0.05）. Among them， the proportion of consciousness disorders patients in the MNOS group was lower than that in the NMDARe group （P<0.0167）， and the proportion of optic neuritis patients in the MNOS group was higher than that in the NMDARe group （P<0.0167）. The proportion of patients with normal EEG in the MOGAD group was the highest （54.6%）. The proportion of patients with non-specific slow waves in the NMDARe group is the highest （35.7%）. The proportion of patients with epileptic waves in the MNOS group was the highest （35.7%）. The NMDARe group exhibited both epileptic waves and δ The proportion of patients with wave was the highest （35.7%）. No δ wave was found in the MOGAD group. There was no significant difference in prognosis among the three groups （P>0.05）. The rate of recurrence in the MNOS group was （21.4%）.Conclusions The incidence of consciousness disorders and optic neuritis in MNOS is different from that in MOGAD and NMDARe. The incidence of epileptic waves is relatively high. Most patients have a good prognosis， but there is a tendency for recurrence. ［Journal of International Neurology and Neurosurgery, 2023, 50(2): 18-22］