In order to explore the functions of histone lysine methyltransferase (HKMT) gene in Lycoris aurea, we cloned a histone lysine methyltransferase gene LaSUVH1 using the RTPCR method based on previous transcriptome sequencing data. The coding sequences (CDs) of LaSUVH1 gene is 2007 bp in length, encoding a deduced polypeptide of 668 amino acids. LaSUVH1 is a stable hydrophilic protein without signal peptide, and had no transmembrane structure. It had SET {Suppressor of Variegation 3-9 ［SU(VAR)3-9］, Enhancer of Zeste ［E(Z)］, and Trithorax (TRX)}, YDG (named for three conserved amino acids)/SRA (SET and RING fingerassociated), PreSET, and PostSET conserved domains. Multiple sequence alignment and phylogenetic tree analysis showed that the deduced protein LaSUVH1 shares higher identity with Asparagus officinalis AoSUVH1like protein. Additionally, quantitative realtime PCR (qRTPCR) analysis indicated that LaSUVH1 was ubiquitously expressed in different tissues, and had the highest expression level in leaf. By hygromycin screening, three transgenic Arabidopsis thaliana lines with antisenseoverexpression of LaSUVH1 gene were obtained. Further functional analysis showed that antisenseoverexpression of LaSUVH1 gene promoted lateral root formation, reduced the tolerance to NaCl stress and increased the sensitivity of seed germination to abscisic acid (ABA) in Arabidopsis, suggesting LaSUVH1 functioning in salt stress response might be involved in ABAdependent signaling pathway.