Breast cancer is one of the three most common cancers with the highest mortality rate in the world and poses a serious threat to human health.MicroRNA （miRNA），as a small molecule of gene regulation，can mediate cellular target genes to regulate the occurrence and development of breast cancer.In this paper，we classified miRNA according to their sources，reviewed the currently known functional properties of endogenous and exogenous miRNA （botanmin），and explored their regulatory mechanisms in breast cancer.At the same time，the potential targets of exogenous miRNA associated with breast cancer were predicted by bioinformatics，which provided a reference for their application in breast cancer therapy.