Thioredoxins are a kind of low molecular weight redox proteins widely existing in plants, which play important roles in the developmental regulation and stress responding processes in plants. Two wheat (Triticum aestivum L.) cultivars, ‘Chinese Spring’ and ‘Luohan No. 2’, were used in this study. A thioredoxin gene TaTrxh9 was cloned from common wheat by using RTPCR. Bioinformatics analysis was performed to define the chromosomal localization and sequence characteristics of TaTrxh9, and its expression patterns responding to osmotic stresses were detected by qRTPCR. The results showed that: (1) TaTrxh9 gene was successfully cloned, sequence analysis indicated that TaTrxh9 was located on the short arms of group one chromosomes, and three homoeologues of the gene were designated as TaTrxh91AS, TaTrxh91BS and TaTrxh91DS, respectively. (2) Four introns were detected in each of TaTrxh9 homoeologues and a large number of polymorphisms were detected in introns among homoeologues, while the coding regions of homoeologues were highly identical (>98%) and encoded an identical protein sequence with the length of 131 amino acids. Characterization of TaTrxh9 protein indicated that a TRXfamily conserved domain and a CXXC redox active site was detected, and the TaTrxh9 was predicted to have a typical spatial structure of thioredoxin, including a peripheral framework composed of 4 helixes and a central axis composed of 5 antiparallel β sheets. (3) qRTPCR analysis showed that TaTrxh9 gene was downregulated in leaves under drought stress, while initially increased and then declined in roots. Under salt stress, no significant response of TaTrxh9 gene was detected in leaves and only a transient induction was observed in roots. The expression pattern of TaTrxh9 under treatment of ABA is similar to that under the drought stress. It was speculated that the responding process of TaTrxh9 gene to drought stress was associated with ABAmediated regulation of gene expression.