Abstract: 　Objective　To study the clinical features and treatments of childhood systemic lupus erythematosus (SLE) complicated with macrophage activation syndrome (MAS). Methods　Clinical data of a patient with SLE complicated with MAS were retrospectively analyzed, and relevant literatures were reviewed. Results　An eight-year-old girl diagnosed as SLE two years ago was admitted to the hospital with complaint of high fever for over one week. Peripheral blood cytopenia, hypofibrinogenemia, hypertriglyceridemia, hyperferritinemia and hepatolienomegaly occurred after admission gradually. Thus the child was diagnosed definitely as MAS. Conclusions　SLE complicated with MAS is not rare. The disease progresses very rapidly and can be life-threatening, while early diagnosis is very difficult. The key to improve prognosis is early diagnosis and treatment.