Objective　To explore the difference of Neutrophil to lymphocyte ratio (NLR) among multiple sclerosis (MS),neuromyelitis optica spectrum disorders (NMOSD),and healthy people,and analyze the clinical value in differentiating MS and NMOSD.Method　Clinical data and laboratory results from patients admitted to Shengjing hospital who were diagnosed with MS or NMOSD,and calculate NLR were retrospectively analyzed.Fifty healthy people matched with sex and age were selected as controls.Result　There were significant differences of neutrophils,lymphocyte,monocyte and NLR among MS,NMOSD and healthy people.The area under curve of ROC in differentiating MS and NMOSD was 0.796 (P<0.001,95%CI 0.685~0.907).Conclusion　The NLR of patients with MS was higher than healthy control,but lower than NMOSD.And NLR was a helpful marker to differentiate MS and NMOSD.