Abstract: This study aimed to review the research progress on the contribution of microRNA (miRNA) to the chemotherapy resistance of breast cancer. With"miRNA, ""breast cancer, "and"chemotherapy resistance"as key words, the literature was searched in Pubmed and CNKI databases between 01-2000 and 10-10-2012. We described the characteristics and mechanisms of breast cancer chemotherapy resistance and focused on the contribution of miRNAs in the chemotherapy resistance of breast cancer. MiRNA participate in chemotherapy resistance of breast cancer through different ways. This article summarizes different miRNAs that participate in chemotherapy resistance and identifies their specific pathways in drug resistance. The potential clinical utilization of the serum miRNA as a tumor marker is also discussed. Further research on the effect and mechanism of serum microRNA in chemotherapy resistance will bring a new chapter in the targeted therapy of breast cancer.