Technical Abstract: Sodium/proton exchangers (NHX antiporters) play important roles in plant responses to salt stress. Previous research showed that hydrophilic C-terminal region of Arabidopsis AtNHX1 negatively regulates the Na+/H+ transporting activity. In this study, CkNHX1 were isolated from Caragana korshinskii, a pea shrub with high tolerance to salt, drought, and cold stresses. Transcripts of CkNHX1 were detected predominantly in roots, and were significantly induced by NaC1 stress in stems. Transgenic yeast and Arabidopsis thaliana sos3-1 (Atsos3-1) mutant over-expressing CkNHX1 and its hydrophilic C terminus-truncated derivative, CkNHX1-^C, were generated and subjected to NaC1 and LiC1 stresses. Expression of CkNHX1 significantly enhanced the resistance to NaC1 and LiC1 stresses in yeast and Atsos3-1 mutant. Whereas, compared with expression of CkNHX1, the expression of CkNHX1-^C had much less effect on NaC1 tolerance in Atsos3-1 and LiC1 tolerance in yeast and Atsos3-1. All together, these results suggest that the predominant expression of CkNHX1 in roots might keep C. korshinskii adapting to the high salt condition in this plant's living environment; CkNHX1 could recover the phenotype of Atsos3-1 mutant; and the hydrophilic C-terminal region of CkNHX1 is required for Na+/H+ and Li+/H+ exchanging activity of CkNHX1.