【Abstract】 Objective To explore the mechanism and clinical diagnosis and treatment of EBV virus associated hemophagocytic syndrome. Methods 1 patients was diagnosed with diagnostic guidelines. The patient was treated with methylprednisolone and immunoglobulin. At the same time, the patient was treated with lowering blood ammonia, anti-infection, correcting liver function and supportive treatment. The clinical data were analyzed. Results After treatment, the temperature of the patient used decrease and vital signs used to be stable, but the patient died with hepatic encephalopathy and respiratory failure. Conclusion Large dose of gamma globulin in combination with large dose methylprednisolone scheme is more suitable for patients with extremely severe HLH of multiple organ dysfunction.