Ionizing radiation (IR) is a genotoxic agent that can play an important role in the occurrence and development of various diseases by inducing epigenetic changes. Studies have shown that the basic mechanisms of IR-induced epigenetic changes include abnormal DNA methylation, increased oxidative stress levels, changes in histone modifications, and regulation by microRNAs. These can lead to health hazards such as malignant tumors, genetic effects, nervous system damage, circulatory system diseases, and radiation-induced cataracts. This article collected relevant literatures regarding epigenetic changes induced by IR from 2005 to 2024, and reviewed the basic mechanisms of IR-induced epigenetic changes and the associated disease risks, providing the reference for radiation protection in occupational exposure and radiotherapy.