Objective:To investigate the effect of miRNA-126 on proliferation, apoptosis and migration of thyroid cancer SW579 cells, and further to explore its mechanism.Methods:Thyroid cancer SW579 cells were cultured in vitro, and the expression of miRNA-126 in normal thyroid Nthy-ori3-1 cells and SW579 cells was detected by qPCR. The cells were divided into blank control group (without any treatment) , experimental group (transfected with miRNA-126 expression plasmid) and negative control group (transfected with empty plasmid vector) . SW579 cells with overexpression of miRNA-126 were constructed by transfection of plasmids. CCK-8 test was used to detect cell proliferation; Transwell cell test was used to detect cell migration and invasion; Flow cytometry was employed to detect apoptosis and changes in reactive oxygen levels; Western blot was used to detect Notch-1/Akt pathway related protein expression.Results:The expression level of miRNA-126 in SW579 cells was 0.25±0.07, and the difference was statistically significant compared with that in Nthy-ori3-1 cells (P<0.001) . The cell survival rates of blank control group, experimental group and negative control group were (105.70 ± 7.61) , (98.60 ± 5.42) and (62.70 ± 3.82) ; The apoptosis rates were (9.14 ± 0.83) , (12.28 ± 1.34) and (36.39 ± 3.21) (all P < 0.05) ; The cell migration rates were (34.51 ± 2.45) , (33.29 ± 3.17) and (11.22 ± 1.23) (all P < 0.05) ; The levels of ROS were (1.02 ± 0.07) , (1.08 ± 0.11) and (6.54 ± 0.74) (all P < 0.05) .Conclusion:Overexpression of miR-NA-126 can inhibit Notch-1/Akt pathway by up-regulating intracellular reactive oxygen species, inhibit the proliferation and migration of SW579 cells, and induce apoptosis in SW579 cells, which provides a certain basis for the study of miRNA-126 in thyroid cancer.