Abstract: Objective To evaluate clinical feature of adult Macrophage Activition Syndrome in order to improve our recognition of it. Methods Clinical data of 13 patients with Macrophage Activition Syndrome were analyzed. Results Fever, arthritis, splenomegaly, jaundice and hepatomegaly were the most common symptoms or signs seen in adult MAS patients. Increased liver enzymes, hyperferritinemia, hypocytosis, hypertriglyceridemia and abnormal coagulation were the most common abnormal laboratory examination. Average ferritin level of the patients was 10237 μg/L. All patients received glucocorticosteroid. 7 patients received additional immune sup-pression treatment. 5 patients died, and 8 patients got remission (2 patiens relapsed in the course of disease). Conclusion Adult Macrophage Activition Syndrome is a life-threatening complication of rheumatic disease and has no typical symptom at onset. When there axe unexplained high fever, hypoeytosis, hyperferritinemia and hy-pertriglyceridemia in rheumatic disease, we should take bone marrow examination to diagnosis the disease as soon as possible.