Osteoporosis is one bone disease characterized with skeletal impairment, bone strength reduced and fracture risk enhanced. [1][2][3][4] It is accompanied or asymptomatic by mild or serious symptoms, which is one cause of pathological fracture and also the high-risk factor influencing human health. [5][6][7] The incidence of osteoporosis is 70% in people over 80 years and 15% in people over 50 years old. 8,9 The osteoporosis patient's number exceeds 200 million worldwide at present, while the number may increase to 300 million as ageing population by 2023. 10 The modulation processes of bone metabolism are associated with several factors such as mechanical stimulation, epigenetic regulation and hormones. [11][12][13][14][15] The major therapies of osteoporosis are drug therapy and surgery, while the curative effect remains unsatisfactory. [16][17][18] Thus, it is crucial to find new biomarkers for the indention and therapy of osteoporosis.Circular RNAs (circRNAs) are formed by reverse splicing of splice accepter at 5′ end splice donor at the 3′ end in the pre-mRNA. [19][20][21][22] cir-cRNAs are one group of noncoding RNA and temporal, disease specific and spatial are expressed in several tissues and cells and can be acted as therapeutic targets and biomarkers. [23][24][25][26] Although circRNAs are mostly located in cytoplasm, some circRNAs containing introns are originated from nucleus. 27 CircRNAs have several functions including regulating gene transcription, regulating translation, modulating alternative splicing, functioning as miRNA sponges and interacting with RBPs (RNAbinding proteins). [28][29][30][31][32] Growing evidence suggested that circRNAs play crucial roles in cell functions such as cell metabolism, differentiation, proliferation, apoptosis and invasion. 19,[33][34][35][36] Increasing studies showed that circRNAs involved in the development of many diseases including cancers, neurological diseases, congenital diseases, intervertebral disc degeneration and endocrine diseases. [37][38][39][40][41][42][43] Recently, studies indicated that circRNAs also play important roles in osteoporosis. 44