LEA5 gene was isolated from Brachymenium exile by polymerase chain reaction (RTPCR) and the promoter sequence of LEA5 gene was isolated by Highefficiency thermal asymmetric interlaced polymerase chain reaction (HiTailPCR). The bioinformatics, expression characteristics and salt stress tolerance of LEA5 were analyzed. This research laid a foundation for further investigating the protective mechanisms of LEA5 proteins. The results showed that: (1) LEA5 gene contains 267 bp open reading frame(ORF), which encodes 88 amino acids. (2) The promoter sequence of the 1 053 bp LEA5 gene was analyzed by PlantCARE showed that it had CAAT box, ABRE, MYB, MYC, MYB binding site and other cisacting elements. (3) Quantitative realtime PCR analysis indicated that LEA5 gene expressed in different stages and tissues of B. exile. (4) In addition, the heterologous expression of LEA5 protein increased the tolerance of Escherichia coli to salt stress. These results suggested that LEA5 protein might have an important function in the tolerance of the salt stress.