【Abstract】 Objective To evaluate the clinical efficacy of potassium sodium dehydroandroan drographolide succinate combined with routine treatment of western medicine in child viral encephalitis, and the impact on the immune function, inflammatory reaction and antioxidation in the serum. Methods 85 child with viral encephalitis were collected and randomly divided into group control (42 cases) and group observation (43 cases). The group control was treated with routine treatment of western medicine, and the group observation was treated with potassium sodium dehydroandroan drographolide succinate combined with routine treatment of western medicine. All groups had a 7 days course of treatment. The clinical efficacy, the changes of T lymphocyte subsets(CD3+, CD4+, CD8+), immunoglobulins (IgA, IgG and IgM) and IL6, TNFα, SOD and MDA in the serum before and after treatment were observed and compared. Results The total effective rate of group observation was 9302% ,which was significantly higher than the group control(P＜005). The time of group observation in improvement of clinical symptoms was significantly shorter than that in the group control(P＜0001). The serum levels of CD3+, CD4+, CD8+, IgA, IgG, IgM and SOD in two groups after treatment were significantly increased than before (P＜005). The serum levels of IL6, TNFα and MDA in two groups were significantly decreased after treatment(P＜005). In addition, the degree of improvement in group observation was more obvious than that of group control. Conclution There was a significant clinical efficacy of potassium sodium dehydroandroan drographolide succinate combined with routine treatment of western medicine in child viral encephalitis, which could improve the immune function and had a certain antiinflammatory and antioxidant function.