Immune thrombocytopenia (ITP) is a heterogeneous autoimmune disease, characterized by dysregulation of cellular immunity. Th17 and associated IL-17 were involved in the pathogenesis of ITP. Runt-related transcription factor 1 (RUNX1), a member of the runt domain-containing family of transcription factors, is required for Th17 differentiation. Whether RUNX1 was involved in the pathogenesis of ITP remains poorly understood. In this study, 30 active ITP patients, 20 ITP in remission and 20 age and gender matched healthy controls were included. Peripheral blood mononuclear cells (PBMCs) were isolated to measure mRNA level of RUNX1 and retinoic acid receptor-related orphan receptor-γt (RORγt) by quantitative real-time PCR and Th17 cells by flow cytometry. Meanwhile, plasma was extracted for measurement of IL-17 level by ELISA. Our results showed a significantly higher expression of RUNX1, RORγt, Th17 cells and plasma level of IL-17 in active ITP patients than that in healthy controls. No differences of expression of RUNX1, RORγt and Th17 cells were observed between remission patients and controls. Furthermore, a significantly positive correlation of RUNX1 with RORγt was found in active ITP patients. In conclusion, RUNX1 was associated with the pathogenesis of ITP possibly through regulation of Th17 cell differentiation and therapeutically targeting it might be a novel approach in ITP treatment.