-To compare the effect of the treatment on viral optic neuritis in a comprehensive therapy of Ganciclovir combined methylprednisolone and comprehensive therapy of methylprednisolone. METHODS:Fourty-one cases 41 patients (60 eyes) with viral optic neuritis were randomly divided into a control group with 20 cases (30 eyes) and a treatment group with 21 cases (30 eyes). Visual acuity and visual evoked potential (VEP)were observed on patients before treatment and on 3^rd, 7^th, 14^th,30^th,90^th,180^th day after treatment . RESULTS:Visual acuity and LP₁₀₀ in two groups were improved over time (P<0.01). Visual recovery had begun on 3^rd day after treatment, visual acuity in the treatment group was better than that in the control group after 1 month (P=0.009), no difference was between the two groups in improved visual acuity after 6 months (P>0.05); the trend that LP₁₀₀ in both groups was improved with time (P<0.01)was showed, a fast recovery rate was showed for LP₁₀₀ in both groups in treatment early (within 2 weeks)stage, the difference was significant compared with pretreatment (P<0.01). However, the recent recovery effect on LP₁₀₀ in the treatment group was better than that in the control group and a little difference was showed in the late treatment stage. CONCLUSION:Visual acuity and LP₁₀₀ can be more quickly improved and the optic nerve electrical activity be strengthened in the comprehensive therapy of Ganciclovir combined methylprednisolone to treat viral optic neuritis compared with the comprehensive therapy of methylprednisolone so as to improve the visual quality of patients.