Thrombotic thrombocytopenic purpura (TTP) is characterized by a microangiopathic hemolytic anemia and thrombocytopenia, which may be treated by plasmapheresis. However, secondary TTP caused by pregnancy, drugs, and autoimmune disorders showed less response to plasmapheresis. A 41-year-old woman presented with mentality change, and then was diagnosed with secondary TTP related to Sjögren\'s syndrome. Later, the patient was successfully rescued by cyclophophamide. The platelet count was within the normal range three months after discharge. The first episode of TTP in SS patient with poor response to plasmapheresis can be treated with cyclophosphamide.