〔Abstract〕Objective： To investigate the expression difference of microRNA in patients with calcifi ed tendonitis. Methods From October 2019 to May 2020, four patients who were diagnosed with CT and received surgical treatment in the Department of orthopedics of Shenzhen Second People's Hospital were selected. Inflammatory tendon tissue (CT group) and para-inflammatory normal tissue (CTR group) were collected from each patient. Total RNA was extracted and sequenced by transcriptome sequencing. The microRNA differentially expressed in the two groups was screened by Illumina HiSeq 2500 high-throughput sequencing technology. Results Compared with normal tendon tissue, there were 760 microRNA signifi cantly changed in calcifi ed tendon tissue. There were 104 differentially expressed genes with log2FC more than 4 times,among which 24 were up-regulated and 80 were down-regulated. The most obvious up-regulated expression was miR-3529 -- 5p, which was 5.9136 times and the most obvious down-regulated expression was miR-486-5p, which was 10.0018 times. The target genes such as COL1A1、GOLGA2、S100A16、 SOX9 and FoxO1 regulated by microRNA are closely related to ion binding and transport,calcium channel activity,protein kinase activity and metabolic function. Conclusion There are signifi cant differences in microRNA expression profi les between calcifi ed tendonitis and normal tendon tissues. The differentially expressed microRNA may play an important role in the formation of calcifi ed tendinitis,which will lay a foundation for further study on the mechanism of microRNA in calcifying tendinitis.