Abstract: Objective MiR-486 was proved to be a hypoxia miRNA in some cells, such as bone marrow derived stem cells and hematopoietic cell. The aim of this study is to observe the effect of miR-486 on the pathogenesis of pulmonary fibrosis under hypoxia. Methods Lentivirus was used to mediate the overexpression or inhibition of miR-486 on 3T3 cells, Flow cytometry and qRT-PCR were used to check the transfection efficiency, and all the lentivirus transfection efficiency were above 85%. The expression of miR-486, FN, α-SMA, Collagen Ⅰ and Collagen Ⅲ on 3T3 cells under hypoxia, or transfected by overexpression and inhibition lentivirus were detected by qRT-PCR. Results Compared with hypoxia oh, hypoxia 6, 12, 24, 48 h miR-486 expression decreased (P<0.05), while the FN and α-SMA expression increased (P<0.05). MiR-486 expression was increased in miR-486 overexpression 3T3 cells (P<0.05). And FN, α－SMA, Collagen Ⅰ and Collagen Ⅱ expression decreased (P<0.05), they were separately (1.000±0.094 vs. 0.125±0.153, P=0.005; 1.000±0.193 vs. 0.044±0.001，P=0.010; 1.000±0.057 vs. 0.561±0.009, P=0.048; 1.000±0.105 vs. 0.275±0.045, P=0.013). FN, α-SMA, Collagen Ⅰ and Collagen Ⅱ expression in miR-486 silence 3T3 cells were 1.000±0.079 vs. 0.027±0.003，P=0.002; 1.000±0.012 vs. 48.909±0.584, P=0.005; 1.000±0.015 vs. 4.416±0.311, P=0.039; 1.000±0.270 vs. 8.892±0.484, P=0.003; 1.000±0.005 vs. 7.671±1.014, P=0.008, mean that miR-486 silence can inhibit miR-486 expression, and promote FN, α-SMA, Collagen Ⅰ and Collagen Ⅱ expression. Conclusion MiR-486 could regulate the pathogenesis of pulmonary fibrosis under hypoxia.