A large number of clinical observations have now found that immunosuppression reduces the frequency of recurrence in most patients with optic neuromyelitis optica (NMO), and is an important component of preventive medication in the remission or chronic phase of NMO. So how should we apply immunosuppression in NMO patients? First, it is necessary to determine which patients need immunosuppression? The current view is that the clinical indications for immunosuppressive therapy include: 1) patients with severe disability from the first episode; 2) patients with significantly elevated serum anti-AQP4 antibody titers that remain high after acute treatment; and 3) patients with significant hormone dependence. Second, what immunosuppressive drugs are available? Currently, there are several clinically available immunosuppressive agents: oral hormone 5-20mg/d; azathioprine 2mg/kg/d; tilmicosin 2g/d; rituximab 375mg/m2/w, 4w; aprotinin 0.4g/kg/d, 5d mitoxantrone 12mg/m2/mon, cumulative dose 140mg/m2 cyclophosphamide 1g/mon , cumulative dose of 10g methotrexate 7.5-25mg/wk cyclosporine A2-5mg/kg/d. Finally, it should be noted that once the application of immunosuppressants is needed should be applied in sufficient quantity as tolerated, otherwise it will not play a role in preventing relapse; in addition, due to the toxic side effects of immunosuppressants, they need to be applied under the guidance of a professional doctor.