Breast cancer is the most malignant subtype of gynecological tumors and with aggressive biological behavior and poor outcome. Ultra-conserved non-coding RNA (ucRNA) is a newly discovered class of long non-coding RNAs (lncRNAs) which involved in the regulation of interaction network of genes. However, the exact function and mechanism by which ucRNA modulates breast cancer aggressive has not yet to be completely elucidated. In the present study, we demonstrated that the expression of uc.246 was significantly upregulated in metastatic breast cancer patients and TNBC cell lines, compared with those in controls. Furthermore, overexpression of uc.246 in MCF-7 cell lines enhanced the capacity of breast cancer cells to induce tube formation and migration of HUVECs, and, finally, enhanced breast cancer cells metastasis. Meanwhile, uc.246 overexpressing enhances the EMT phenotype of TNBC cells. Mechanistically, we found that uc.246 promoted malignant progression of breast cancer via upregulating the levels of VEGF-C and increased the levels of mesenchymal marker protein. Our results demonstrated that uc.246 induced angiogenesis, migration, and EMT phenotype and may represent a novel prognostic biomarker and therapeutic target for patients with breast cancer.© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.