Objective:To analyze the different expressions of miRNAs in peripheral blood of rheumatoid arthritis (RA) patients and the osteoclasts in rats,and to verify the key miRNAs in RA.Methods: The miRNAs expressions in monocyte and the co-cultured osteoclasts,peripheral blood of rheumatoid arthritis (RA) patients and normal were detected by miRCURYTM LNA Array.Real time PCR was applied to verify the reliability of miRNA array.The bioinformatics software and database were applied to predict and analyze target genes.Results: miRNA array results showed that 189 miRNAs changed in RA patients compared with the normal;211 miRNAs were changed in osteoclasts group compared with monocytes group.The expressions of ten miRNAs were all abnormal in RA patients and osteoclasts in rats.The results of Real time PCR were consistent with the array.Results of bioinformatics analysis showed that the target gene of miRNA significantly enriched in signaling pathways such as VEGF,MAPK signaling pathways.Conclusion: Some miRNAs had similar abnormal expressions in different species,and these miRNAs may influence the differentiation of the osteoclasts through regulating the related signal passways.