Objective: To investigate the possible molecular mechanism of epidermal growth factor-like domain 7 (EGFL7) involvement in tumor cell invasion. Methods: The recombinant miR-126 overexpression plasmid was designed and transfected. The plasmid was transfected into MDA-MB-231, and the protein expression of EGFL7, Wnt-1, β-catenin and E-cadherin was detected by Western blot. The protein expression of Vimentin was detected by immunohistochemistry and the morphological changes were observed. The mRNA expression of Twist and Slug transcription factors was detected by RT-PCR. The in vitro invasion ability of tumor cells was observed by Transwell chamber invasion assay. Results: The transfected breast cancer cell line MDA-MB-231/miR-126 with expression of miR-126 was successfully established, and the expression of EGFL7 protein in stably transfected cell line was down-regulated (P<0.01), and protein expression of Wnt-1/β-catenin were down-regulated (P=0.02/P<0.01), E-cadherin protein expression was up-regulated (P<0.01), Vimentin protein expression was down-regulated, and cell morphology was transformed from fusiform mesenchyme to polygonal epithelial; the mRNA of Twist and Slug transcription factors were down-regulated (P<0.01), and the invasive ability of tumor cells in vitro was weakened (P<0.01). Conclusion: miR-126 regulates Wnt-1/β-catenin signaling pathway and Twist and Slug transcription factors by targeting EGFL7, inhibits epithelial-mesenchymal transition of breast cancer cells MDA-MB-231, and reduced invasive ability of breast cancer cell MDA-MB-231 in vitro, EGFL7 can be used as an important biomarker for predicting breast cancer metastasis and may be a potential therapeutic target.