At present,the cases of optic neuritis caused by demyelinating diseases in pregnancy are very rare at home and abroad.How to reduce the influence on the fetus while treating the mother has become the key of pregnancy man-agement.This article describes a case of optic neuritis caused by demyelinating disease in twin pregnancy.In this case,the ultra-low birth weight infant was successfully saved and the optic nerve injury was relieved by treatment.Through the intro-duction of this case,it can provide reference for perinatal medical workers how to do pre-pregnancy consultation,perinatal management,postpartum rehabilitation treatment and improve newborn survival rate.