The present invention discloses a method for epigenetically manipulating phenotypic plasticity traits of plants, including: quantitatively replacing methylation sites of a target gene by means of a degeneration codon, and carrying out a transgenic operation by designing a synthetic gene； or constructing a plant expression vector by using a CRISPR/Cas9 technology to quantitatively replace the methylation sites with in-situ in-vivo gene degeneration codons and quantitatively regulate a degree of methylation and an expression level of an exogenous or in-situ in-vivo target gene to attain quantitative regulation of the plasticity traits of a target plant. By means of quantitative regulation of the methylation degree of an ICE1 gene, plants having different cold-resistance capabilities are cultivated, thus providing a new choice for the cultivation of cold-resistant crops by means of epigenetic techniques, and providing a technical method for reducing the impact of cold harm on crop yield, quality and the like.
