As a crucial aspect of epigenetic research, DNA methylation is fundamental to genomic stability, gene transcription regulation, and chromatin remodeling. Rice is a staple food source for roughly half of the world's population. Therefore, optimizing rice yield and stress tolerance is vital for global food security. With the continuous advancement of DNA methylation detection technologies, studies have shown that DNA methylation regulates various rice growth and development processes, including root differentiation and grain development, through the dynamic equilibrium of de novo methylation, maintenance methylation, and demethylation. Furthermore, DNA methylation is crucial in the plant's response to environmental stressors like high or low temperature, drought and salinity. The patterns of DNA methylation modifications are also closely linked to rice domestication and heterosis formation. Therefore, a comprehensive investigation of the DNA methylation regulatory network holds significant theoretical value for rice genetic improvement and molecular breeding. This review offers a systematic analysis of the molecular mechanisms and detection technologies of DNA methylation, as well as its regulatory roles in rice growth and development, stress responses, and other biological processes, aiming to provide a theoretical foundation for rice genetic improvement research.