Antiphospholipid antibody syndrome(APS) is a well-known clinical syndrome characterized by recurrent arterial or venous thromboses, recurrent fetal loss, thrombocytopenia, together with high titers of sustained anticardiolipin antibody(aCL) or lupus anticoagulant(LA). Although systemic lupus erythematosus(SLB) and APS may coexist, a high proportion of patients manifesting the APS do not suffer from classical lupus or other connective tissue disease. The patient has been defined as having a primary antiphospholipid antibody syndrome. We experienced one case of primary APS with recurrent fetal loss, recurrent cerebral infarctions, positive anticardiolipin antibody IgG and fluttering vegetation on the mitral valve, without other connective tissue diseases including SLE. Forty-three old female had 2 out of 11 criteria for the diagnosis of SLE, such as thrombocytopenia and positive antinuclear antibody, but did not meet whole criteria. The patient was treated with ticlopidine, and anticoagulant therapy was recommended.