Objective To study the significance of reticulated platelet and thrombopoietin in the diagnosis of idiopathic thrombocytopenic purpura. Methods Reticulated platelet percent was analyzed via flow cytometry, plasma thrombopoietin was examined by ELISA, platelet and mean platelet volume were measured by automized machine,and megakaryocyte was counted through bone marrow staining. Results Reticulated platelet percent of idiopathic thrombocytopenic purpura patients' group were higher than other groups,thrombopoietin of this group was about the same to control group, and increased megakaryocytosis of this group was associated with larger mean platelet volume and higher reticulated platelet percent. Conclusion Examination of reticulated platelet percent and thrombopoietin is helpful to classify the patients with thrombocytopenia into different categories and may be of a value in the diagnosis of idiopathic thrombocytopenic purpura.