Abstract: Objective To study the clinical significance of the changes of reticulocyte(RET)and lymphocyte subsets count in children with idiopathic thrombocytopenic purpura(ITP). Methods Total 110 cases of ITP in our hospital between February,2014 and October,2015 were enrolled and divided into cured group,valid group and invalid group according to the curative effect,and 25 children were selected as control group.FACS Canto II flow cytometry and Sysmex-XT4000i automatic blood cell analyzer were used to test the expression of lymphocyte subgroup and percentage of reticulocyte with fluorescence intensity. Results ①After the treatment,the levels of CD3⁺ T lymphocytes and (CD3⁺CD4⁺) T helper(Th) lymphocytes decreased significantly,inversely,(CD3⁺CD8⁺) T suppressor(Ts) lymphocyte and (CD3⁺,CD19⁺) B lymphocyte increased obviously.There were significant difference in the expression of CD3⁺,Th,Ts and B lymphocytes between patients and control(P<0.05),but the expression of NK cells (CD3^-CD56⁺/CD16⁺) were not improved in each group,and the difference among the all groups was not significant(P>0.05);②In the patients,LFR% decreased obviously,but RET%,HFR%,MFR% and IRF were significantly elevated,and the difference was significant when compared with the control group(P<0.01). Conclusion The reticulocyte related parameters and the level of T lymphocyte subsets of children with ITP play an important role in the diagnosis and prognosis judgment.