The aim of this study was to detect the rate of T-helper (Th)17 cells and interleukin (IL)-17 level in peripheral blood of patients with primary immune thrombocytopenia (ITP) and to explore their clinical significance. The proportion of Th17 cells from 48 patients with ITP and 28 healthy controls was detected by flow cytometry, and the IL-17 level was evaluated by enzyme-linked immunosorbent assay (ELISA). The results showed that the percentage of Th17 cells in ITP group was (1.40 ± 1.35)%, which was significantly higher than that in healthy control group (P < 0.05), but in the glucocorticoid hormone-treated group it was significantly lower than that in treated group without glucocorticoid hormone(P < 0.05). The level of IL-17 expressed by Th17 cells in ITP patients was (19.624 ± 5.187) pg/ml, which was higher than that in the healthy control group (P < 0.05), it was lower in the glucocorticoid hormone treated group than that in treated group without glucocorticoid hormone, but there was no statistically significant difference between the glucocorticoid treated and treated group without glucocorticoid hormone (P > 0.05). It is concluded that the Th17 cells may involve in the pathogenesis of ITP, and the glucocorticoid hormone probably plays a therapeutic role through inhibiting Th17 cells.