To detect levels of platelet glycoprotein-specific autoantibody in idiopathic thrombocytopenic purpura (ITP), chronic aplastic anemia (CAA), hematologic malignancies and healthy volunteers, and evaluate the clinical significance of platelet glycoprotein-specific autoantibody level in diagnosis for ITP, anti-GPIb/IX, anti-GPIIb/IIIa, anti-GPIV and anti-GPV auto-antibodies were detected contemporaneously by a modified monoclonal antibody immobilization of platelet antigen assay (modified MAIPA). The results showed that the total positive rate of antibodies against platelet GPIb/IX, GPIIb/IIIa, GPIV, GPV were 69.99%, 10%, 20% and 0% in ITP, CAA, hematologic malignancy group and healthy volunteers respectively. There was significant difference between ITP and CAA (chi(2) = 20.71, P < 0.005), between ITP and hematologic malignancy group (chi(2) = 12.22, P < 0. 005). There was no positive finding in the healthy control. It is concluded that platelet glycoprotein-specific autoantibody has high value for the diagnosis of ITP,many kinds of antibodies detection at one time can enhance sensitivity, MAIPA is a specific assay for the diagnosis of idiopathic thrombocytopenic purpura.