Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are common demyelinating diseases of central nervous system (CNS). In recent years, the development of magnetic resonance imaging (MRI) techniques and the progress in autoimmune antibody detection have gradually deepened the clinical understanding of these diseases. Many diagnostic criteria and guidelines for MRI provide important basis for clinical identification of MS and NMOSD. Distinct autoimmune antibodies and neuroimaging features make myelin oligodendrocyte glycoprotein-immunoglobulin G-associated encephalomyelitis (MOG-EM) a novel and isolate group of diseases separated from MS and NMOSD. Therefore, how to distinguish MOG-EM from MS and NMOSD by using MRI technique, and how to achive early diagnosis, guide treatment and predict prognosis by using MRI technology, have become hot issues in the current research on demyelinating diseases of CNS. This paper aims to review and discuss the progress in the utility of MRI in the clinical diagnosis of common demyelinating diseases of CNS.