This study was aimed to detect the CD3(+) count, ratio of CD3(+)/CD30(+) T-lymphocytes, the apoptosis rate of activated T-lymphocytes in peripheral blood mononuclear cells and the circulating platelet counts in patients with chronic idiopathic thrombocytopenic purpura (ITP), and to investigate the relationship between them. 40 cases of chronic ITP patients were taken as the research group and 24 healthy persons were served as the control group. The CD3 count, ratio of CD3/CD30 T-lymphocytes and the apoptosis rate of activated T-lymphocytes were detected by flow cytometry, the platelet count was measured at the same time. The difference between 2 groups and correlation of the activated T lymphocyte CD30 expression rate with apoptotic rate and platelet count in patients were analysed. The results showed that there was no significant difference in the count of peripheral blood CD3(+) cell between the research group and the control group (p > 0.05). The expression of CD30 on activated T-lymphocytes in ITP group was obviously higher than that in control group (p < 0.01). The apoptosis rate of activated T-lymphocyte in ITP group was remarkably lower than that in control group (p < 0.01). The expression of CD30 on activated T-lymphocyte exhibited a negative correlation with the apoptosis rate (r = -0.786, p < 0.01). The apoptosis rate of activated T-lymphocyte was positively correlated with the platelet count of peripheral blood (r = 0.680, p < 0.01). It is concluded that the high expression of CD30 on activated T-lymphocytes in patients with chronic ITP results in the inhibition of apoptosis, which leads to immune disorder and thrombocytopenia.