Radiotherapy is an effective way to reduce the local recurrence rate and mortality of breast cancer.However,the risk of long-term side effects of radiation-induced cardiac injury cannot be ignored.Especially for patients undergoing left breast ra-diation therapy,the risk of cardiac injury is higher due to the heart being within the radiation field,which increases the incidence of radiation induced heart disease and ultimately affects long-term survival rate and quality of life.Therefore,it is particularly important to prevent radiation induced cardiac injury.The main measures include using advanced radiation therapy techniques such as intensity modulated radiation therapy,volume modulated arc radiotherapy,deep inhalation and breath holding radiation therapy,prone position radiation therapy,proton beam therapy,etc.or optimizing the radiotherapy plan for cardiac substructure to reduce the radiation dose to key cardiac structures.This article will review the research progress of pathophysiological mechanism,clinical manifestations,risk fac-tors and preventive measures of radiation-induced cardiac injury in breast cancer.