The plasmalemma Na⁺/H⁺ antiporter gene was isolated from Nitraria sibirica, referred to as NsSOS1, using homologybased cloning techniques, and its expression characteristics under different stress conditions were investigated. The NsSOS1 contains an open reading frame (ORF) of 3 516 bp, encodes a protein of 1 171 amino acids with a molecular weight of 128.34 kD. Bioinformatics analysis indicated that the NsSOS1 protein contains 12 transmembrane domains and functional domains conserved in plant SOS1 proteins. Phylogenetic analysis showed that the NsSOS1 belongs to the same clade to plasmalemma Na⁺/H⁺ antiporters from the other plants and has a close relationship with the KvSOS1 of Malvaceae Kosteletzkya virginica. Quantitative realtime RTPCR showed that the NsSOS1 majorly expressed in roots and leaves of the N. sibirica and its expression levels were regulated by abiotic stress (NaCl, low temperature, drought) and exogenous hormones (MeJA and GA), suggesting that the NsSOS1 gene plays an important role in resisting stress in N. sibirica.