【Abstract】Objective To investigate the regulatory effects of miR-301a on invasion and proliferation and potential mechanism in the triple negative breast cancer. Methods The expression of miR-301a in cell lines MDA-MB-231 and MCF-10A were determined by real-time PCR. Transfected MDA-MB-231 and set up NC controls, Transwell assay and WTT assay were used to detect the effect of miR-301a on cell invasion and proliferation. The downstream targets of miR-301a was predicted by bioinformatical tools. The regulation between miR-301a and targets was verified by Luciferase reporter assay and Western blot. Results The expression of miR-301a in MDA-MB-231 was significantly higher than that in MCF-10A (P＜0.05). The Transwell assay and MTT assay revealed that overexpression of miR-301a could enhance the invasion and proliferation ability of MDA-MB-231. Luciferase reporter assay and western blot indicated that miR301a inhibited the luciferase activity of MEOX2. Overexpression of miR-301a reduces MEOX2 protein levels (P＜0.05), and inhibition of miR-301a expression can increase MEOX2 protein levels (P＜0.05). Conclusion miR-301a is high-expressed in TNBC cells and is a cancer promoter which can enhance the invasion and proliferation of TNBC cells through targeting MEOX2.