Dehydrin is the most distinctive group of proteins in the late embryogenesis protein (LEA) family, which plays an important role in plant resistance to abiotic stress. In this paper, we isolated the complete coding sequences of four dehydrin genes, designated AmDHN3.2F, AmDHN5.1F, AmDHN6.2F and AmDHN7.2, in stress-resistant evergreen broad-leaved shrub Ammopiptanthus mongolicus. The bioinformatics analysis using DNAMAN software suggested that all four genes carried one K and one S domain. The analysis of physicochemical properties showed that all four proteins belonged to hydrophilic proteins. AmDHN3.2F was alkaline protein, while AmDHN5.1F, AmDHN6.2F and AmDHN7.2 were acidic proteins. AmDHN7.2 exhibited the largest theoretical relative molecular weight (21.42 KD), and AmDHN3.2F showed the smallest weight (10.69KD). AmDHN3.2F exhibited the highest theoretical isoelectric point (PI = 9.01), and AmDHN6.2F showed the smallest isoelectric point (6.21). By in silico prediction of secondary and tertiary structure, the four dehydrin proteins composed of three types of motifs: alpha helix (7.50%-32.63%), irregular curl (55.79%-73.00%) and elongation chain (11.58%-19.50%). The phylogenetic tree constructed by Neighbor-joining method suggested that the putative proteins of four dehydrin genes were related to MtDHN3 and AtDHN10. By XSTREAM software, it was found that the protein sequences of AmDHN5.1F, AmDHN6.2F and AmDHN7.2 contained tandem repeat units, which were enriched in the middle part of dehydrin. According to the dot maps generated by DOTTER software, a large number of short repeats were found in the middle part, implying the location where the shrinkage or expansion of dehydration sequence mainly occurred. This findings lay a foundation for further functional analysis of DHN gene family in Ammopiptanthus mongolicus.