Epigenetic regulation modes, epigenetic regulatory effects, and the research progresses in plant epigenetic are summarized. According to classical genetics, nucleic acids are the foundation of heredity, and the hereditary information of life is stored in the base sequence of nucleic acids. The change of base sequence might lead to phenotypic variations of organisms, and these variations might pass on to the next generation. Within one organism, the different types of cells have their own unique gene expression patterns, although they share the same genetic background. It is caused by activating some special sets of genes, meanwhile suppressing the other. This phenomenon is known as epigenetic modification. Epigenetics is a phenomenon for altering gene expression pattern; however changes in the underlying DNA sequence of the gene are not involved. Its process includes DNA methylation, histone modification, and non-coding RNA regulation, etc. Its manifestation includes genomic imprinting, maternal effect, gene silencing, nucleoli dominance, and dormant transposon activation, etc. Epigenetic modification is the result of interactions between environmental factors and intracellular genetic materials. Through gene expression regulation, epigenetic modification is able to control the phenotype of an organism. Due to its importance for maintaining stable environment inside an organism and normal functions of organs, abnormal epigenetic modification could lead to disease. It is why today epigenetics becomes a hot research spot on the drug design and therapy development.