miR-106b-5p was elevated in peripheral blood of patients with ITP, and NR4A3 expression was decreased. sh-NR4A3 significantly decreased Foxp3 and TGF-β expressions, indicating that NR4A3 may regulate Treg differentiation via Foxp3. NR4A3 was identified as a target of miR-106b-5p, and miR-106b-5p was able to negatively modulate NR4A3 expression. miR-106b-5p induced immune imbalance of Treg/Th17 through NR4A3. Silencing miR-106b-5p promoted Treg differentiation and increased the number of platelets. The gene discussed is NR4A3; the disease is autoimmune thrombocytopenic purpura.