〔Abstract〕 Objective To investigate the role and mechanism of microRNA(miR)-205 in promoting the differentiation of human adipose-derived stem cells(hASCs) cell lines to chondrocytes by regulating the expression of core-binding factor α-1(Cbfα-1).Methods Lenti-miR-205 and lenti-control lentivirus solution were transfected into the hASCs cells by lentivirus transfection method, which were named miR-205 overexpression group and miR-NC group. The untreated cells were taken as the control groups. The expression of miR-205 gene was detected by RT-qPCR and cell proliferation was detected by MTT colorimetry. The induced differentiation of the third generation hASCs cells after transfection was observed by toluidine blue staining, immunocytochemistry and immunofluorescence staining. The expressions of Cbfα-1, Smad3, TGF-β1, ColⅡ mRNA and protein were detected by RT-qPCR and Western blot.Results The relative expression leve of miR-205 gene in miR-205 overexpression group was higher than that in control group and miR-NC group(P<0.001). The absorbance(A) value of MTT test of the miR-205 overexpression group was higher than that of the control group and the miR-NC group(P<0.05). After 2 weeks of induction,the toluidine blue staining showed that the miR-205 overexpression group stained strongly positively in dark blue staining,while the control group and miR-NC group were weakly light blue. Immunocytochemical staining showed that the cells and extracellular matrix of miR-205 overexpression group were strongly positive brown-yellow staining,while those of the control group and miR-NC group were weakly positive yellowish staining.Immunofluorescence staining showed that the red fluorescence intensity of miR-205 overexpression group was stronger,and the red fluorescence intensity of control group and miR-NC group was dim. The toluidine blue staining in the control group and miR-NC group was weak light blue. The relative expression levels of Cbfα-1 mRNA and protein in the miR-205 overexpression group were lower than those in the control group and miR-NC group,and the relative expression levels of Smad3,TGF-β1,ColⅡ mRNA and protein in the miR-205 overexpression group were higher than those in the control group and miR-NC group( P<0. 05). Conclusion MiR-205 overexpression can promote hASCs cell proliferation and differentiation towards chondrocytes,which may play a regulatory role by inhibiting Cbfα-1 and activating TGF-β1/Smad3 signaling pathway.