Abstract: To explore the effects of exogenous salicylic acid（SA）added on plants, the physiological indices including membrane lipid peroxidation, reactive oxygen species accumulation, antioxidant enzyme activities, and antioxidant contents as well as gene expression in the leaves of Davidia involucrata seedlings under salt stress were investigated respectively. The results revealed that, under salt stress, the application of SA significantly reduced the relative electrolyte leakage, and inhibited the accumulation of malondialdehyde（MDA）and ROS, and increased the relative water content, activities of antioxidant enzymes（i.e., SOD, POD, and APX）, and glutathione（GSH）contents. Moreover, treatment with SA resulted in differential expression of 2 581 genes（1 516 up-regulated and 1 065 down-regulated） under salt stress. KEGG analysis indicated that differentially expressed genes（DEGs）were enriched in nine pathways including phenylpropanoid biosynthesis.In addition, transcriptome sequencing and quantitative real-time PCR（qRT-PCR）results showed that exogenous SA significantly induced the expression of transcription factor genes including DiWRKY40, DiNAC25, DiMYB4, and DiMYB86 under salt stress. These results suggested that exogenous SA might stimulate stress responses in salt-treated D. involucrata seedlings and trigger variation in gene expression, resulting in alleviation of salt injury in D. involucrata seedlings.