Abstract: Saline soils are normally dominated by Na⁺ which threatens plant growth and agricultural productivity. Increasingly research has focused on the functions of high-affinity K⁺ transporter HKT2;1 in controlling Na⁺ uptake, strengthening the selectivity of K⁺ and thus enhancing salt tolerance. A putative high-affinity K⁺ transporter gene PutHKT2;1 was isolated from the halophyte Puccinellia tenuiflora by RT-PCR and RACE methods and was used to investigate the sodium tolerance mechanism. The gene was 1 919 bp in total length with an open reading frame (ORF) of 1 638 bp encoding a 60.5 kDa protein with 546 amino acids and theoretical PI of 9.07. Sequence analysis suggested that the nucleotide sequence and the translated amino acid sequence shared over 75% and 66% of homology to the HKT2;1 gene sequences from other higher plants. The PutHKT2;1 protein might have 11 transmembrane segments. Secondary structure analysis indicated that the PutHKT2;1 contained a 47.99% α-helix, 5.13% β-turns, 31.87% random coils and 15.01% extended strand. Cloning the full length PutHKT2;1 gene and its bio-informatical analysis will be helpful to elucidate the salt tolerance mechanism of P. tenuiflora.