The invention discloses a method for improving the resistance of wheat plants to salt stress. The method comprises the following steps: extracting the total RNAs of wheat, independently designing a synthetic RT stem-loop primer for reverse transcription synthesis of cDNA, connecting the cDNA to a cloning vector pMD18-T via a PCR amplification product, transforming the obtained product into the competent Escherichia coli JM109, extracting plasmid and performing sequencing so as to obtain the miR398 sequence of wheat; and under the condition of high salt stress, researching the relative changesof the expression levels of the miR398 and a target gene CSD, determining the relationship between the expression level changes of the miR398 in wheat and salt damage stress response, and determiningthe negative regulation relationship between the miR398 and the CSD gene in wheat, thereby laying a foundation for the overexpression of the CSD gene and the improvement of the salt damage stress ability of wheat. According to the invention, a constructed miR398 sponge element is introduced into a wheat genome to achieve the purpose of adsorption of the miR398, inhibit the silencing effect of themiR398 on the target gene CSD and increase the relative expression level of the CSD gene, so the ability of wheat plants in resisting salt damage stress is further enhanced and wheat yield is increased.