The idiopathic hypereosinophilic syndrome (HES) comprises a heterogeneous group of disorders with unknown pathogenesis characterized by persistent peripheral blood and bone marrow eosinophilia. And the eosinophil infiltrates of multiple organs in HES lead to severe organ dysfunction. The disseminated intravascular coagulation (DIC) is a rare complication of HES. We have experienced a case of HES complicated with DIC and pulmonary thromboembolism. After intravenous injection of methylprednisone, blood eosinophil count was normalized but DIC was persisted. With cortico steroid and cyclosporine therapy, the disease activity was favorably remitted.