Thirty patients with confirmed primary sjogren syndrome and thrombocytopenia during January 2002 and December 2007 were investigated.All the participants received 0.5 mg·kg-1·d-1 Prednisone and 100 ms/d CosA for 1 year.Clinical symptoms and the levels of white blood eell.platelet count,erythrocyte sedimentation rate,liver function,immunoglobin,and rheumatoid factors were recored before and after the treatment.After one-year follow.up,platelet count was elevated(t=11.4179,P< 0.01).There was no significant change in erythrocyte sedimentation rate.The concentrations of immunoglobin and rheumatoid factors were significantly decreased at 1 year(t=5.4222,P<0.01;t= 9.2857.P<0.01).Prednisone plus CosA could effectively treat primary sjOgren syndrome combined with thrombocytopenia and result in fewer side effects.