We aimed to identify specific circular RNAs (circRNAs) involved in bone repair of trauma-induced osteonecrosis of femoral head (TIONFH) and to explore the potential mechanism. CircRNA sequencing on the blood sample collected from patients with and without TIONFH was performed to select cirRNAs that were significantly differentially expressed, followed by qRT-PCR confirmation. Furthermore, the functions of one selected circRNA and the potential mechanisms in bone repair of TIONFH were validated based on the bone marrow mesenchymal stem cells (BMSCs) and osteoclast-like cells (OLCs) through CCK-8, flow cytometry, transwell assay, luciferase reporter assay, and western blot. A total of 234 upregulated and 148 downregulated differentially expressed circRNAs were identified, and qRT-PCR showed that circRNA_25487 was significantly upregulated in the peripheral blood of TIONFH patients. Luciferase reporter assay confirmed the binding effect between miR-134-3p and circRNA_25487. CircRNA_25487 suppression and miR-134-3p overexpression could promote cell proliferation and invasion while inhibited apoptosis of BMSCs and OLCs. miR-134-3p could target p21. CircRNA_25487 inhibited bone repair in TIONFH by sponging miR-134-3p to upregulate the expression of p21. © 2020 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.