Objective  Centromere protein M(CENP-M) is an important member of constitutive centromere-associated network（CCAN）protein family. And it guarantees the correct formation and function of centromeres and kinetochores, and plays an important role in normal cell division. However, there are only a few studies on the relationship between CENP-M and cancers. Therefore, the aim of this study is to explore the relationship between CENP-M expression and prognosis of breast cancer.   Methods  CENP-M expression and prognosis in breast cancer were analyzed through datebases, including Oncomine, COSMIC, bc-GenExMiner, Kaplan-Meier plotter, cBioPortal, GEPIA and Timer.   Results  Compared with the normal tissue samples, the expression of CENP-M was up-regulated in various cancers, and the highest expression was found in breast cancer(especially in invasive ductal breast cancer，invasive cribriform breast adenocarcinoma and mucinous breast carcinom); According to analysis of genic mutation, the increase of CENP-M expression was not due to the change of the sequence or copy number of the gene; The expression of CENP-M was correlated with different types and Scarff-Blom-Richordson(SBR) stages of breast cancer; Breast cancer patients with high CENP-M expression had poor prognosis; The expression of CENP-M was correlated with the expression of CDC45 in breast cancer.   Conclusion  CENP-M can be a prognostic biomarker for breast cancer patients.