) belongs to the Acipenseridae which is one of the oldest families of fishes. Sterlet are suitable for large scale aquaculture as they will breed in captivity. Despite their relatively small body size (maximum body length 1 m and mass of 20 kg), starlet are of great interest to fishermen, fish farmers, and consumers due to the excellent taste of their meat and caviar. Androgen receptor (AR), a ligand-dependent transcription factor of androgens, is important for sexual differentiation, gonadal maturation, reproductive behavior, and maintenance of male sexual characteristics. This study on focused on the sequencing and characterization of cDNA encoding, and the expression of . The full length of cDNA mRNA expression was detected using real-time the AR was 2 953 bp in length, including a 68 bp 5′ terminal untranslation region(UTR) AR precursor protein was encoded by 843 amino acids and had a predicted molecular weight of 94.24 kD. Alignment analysis showed that the sequence was 99%, 98%, 83%, 83% and 81% similar to those of Oncorhynchus mykiss, , respectively, and the coding sequence had a higher homology with fish. Several domains present in all cloned . The domains corresponded to an amino-terminal hypervariable transcriptional activation domain (TAD), a central highly conserved DNA-binding domain(DBD), and a carboxy-terminal ligand-binding domain(LBD). Percentages of homology-similarity among these functional domains in teleost fish ranged between 60% and 80% for the LBD, 70% and 99% for the DBD, and 10% and 60% for the TAD when compared with those of sterlet. Application of real-time qPCR found that AR mRNA was expressed in all experimental tissues. Male and female fish all had a high expression level in gonad, muscle and kidney, and low expression levels in other tissues. AR gene mRNA was expressed widely in sterlet tissues, suggesting that it plays an important role in growth and reproduction.