Histone deacetylation modification is an important kind of epigenetic regulation in plants, which played important roles in chromosome structural modification and gene expression regulation. To explore the function of the histone deacetylase 1 gene (HDT1) in the somatic embryogenesis process of longan, based on longan genomic data, we cloned the DlHDT1 by RTPCR, and analyzed its bioinformatics, protein subcellular localization observation and the expression pattern during the somatic embryogenesis of longan (FPKM value). The expression pattern of DlHDT1 gene under PEG6000 and NaCl treatments were detected by qRTPCR. The results indicated that： (1) the length of DlHDT1 CDS was 918 bp, which encoding 305 amino acid residues. DlHDT1 protein was an unstable hydrophilic protein without signal peptide and transmembrane structure, and contained a total of 43 phosphorylation sites. The relative molecular weight was 32 585.54 Da and the isoelectric point was 4.65. Phylogenetic tree analysis showed that DlHDT1 exhibited the highest sequence similarity with Acer yangbiense (78.76%). (2) Subcellular localization result showed that DlHDT1 protein was localized in the nucleus. cisacting element analysis showed that DlHDT1 gene contained a large number of light response elements, hormones such as abscisic acid, methyl jasmonate and stress responsive elements also existed. Transcriptome data analysis showed that DlHDT1 had the highest expression in the globular embryo (GE) stage, and had the lowest expression in the embryogenic callus (EC) stage. (3) qRTPCR results showed that the expression of DlHDT1 gene was downregulated under the treatments of PEG6000 and NaCl, indicating that DlHDT1 may negative regulated by drought and salt stress in longan. To sum up, DlHDT1 is a nuclear localization gene, which may participate in the somatic embryo morphogenesis of longan and play an important role in the response of longan to abiotic stress.