Based on the transcriptome data of longan embryogenic callus, we cloned the Dimocarpus longan DRM1 gene. The functions of DlDRM1 was analyzed by means of bioinformatics and realtime quantitative PCR. Expression of DlDRM1 was analyzed in the stages of somatic embryogenesis, exogenous hormone (2,4D, IAA, KT) treatment and different tissues in D. longan. The purpose is to reveal the D. longan DRM1 gene function in the process of longan somatic embryos. The results showed that: (1) the fulllength sequence of longans _{Domains Rearranged Methyltransferase} 1 gene (DlDRM1) was successfully cloned from embryogenic callus of ‘Honghezi’ longan by using RTPCR (GenBank accession number is KY990493) based on the transcriptome data of longan embryogenic callus unigene sequences. The cDNA fulllength is 2 574 bp, including 494 bp 5′UTR and 184 bp 3′UTR, and it could encodes protein with 631 amino acids. (2) Bioinformatics analysis showed that DlDRM1 (molecular formula: C₃₁₀₄H₄₈₃₉N₈₅₁O₉₈₄S₂₈) was an unstable hydrophile protein, without signal peptide and transmembrane domain. Sequence alignment result showed DlDRM1 was highly similar to DRM in navel orange (up to 76.85%), and the closest genetic relationship was also found between the two proteins according to phylogenetic analysis. (3) Quantitative realtime PCR showed that DlDRM1 expresses in all of the tissues and organs in longan and the highest expression was found in flesh, followed by flower buds, and the lowest expression was found in leaves. Notably, the expression of DlDRM1 in nonembryonic callus was found to be significantly higher than that in embryonic callus, and its expression decreases during the process of the non embryonic callus changes to be embryonic. These indicated that DlDRM1 was negatively correlated with the embryonic of somatic embryo and it might contribute to the longan somatic embryogenesis. Moreover, we also studied the effects of hormones on the expression of DIDRM1. And it was found that certain concentrations of IAA and 2,4D could promote its expression, while KT inhibit its expression. (4) Subcellular localization result showed that DlDRM1 was located in nucleus and cell membrane.