Breast　cancer　is　one　of　the　most　important　malignant　tumors　affecting　women＇s　health.　Epigenetic　modification　and　oxidative　stress　caused　by　excessive　accumulation　of　reactive　oxygen　species　(ROS)　play　a　key　role　in　the　occurrence　and　development　of　breast　cancer.　In　addition,　epigenetic　modification　and　the　production　and　clearance　of　ROS　interact　with　each　other.　In　this　paper,　epigenetic　modification　and　ROS　involved　in　the　occurrence　and　development　of　breast　cancer　are　reviewed　in　order　to　provide　possible　ideas　for　seeking　biomarkers　and　precise　therapy　for　the　treatment　of　breast　cancer.