Bi_2Se_3, as a three-dimensional topological insulator, has attracted worldwide attention for its unique surface states which are protected by time-reversal symmetry. Here we report the synthesis and characterization of high-quality singlecrystalline Bi_2Se_3 nanowires. Bi_2Se_3 nanowires were synthesized by chemical vapor deposition(CVD) method via goldcatalyzed vapor-liquid-solid(VLS) mechanism. The structure and morphology were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), x-ray photoelectron spectroscopy(XPS), and Raman spectroscopy. In magnetotransport measurements, the Aharonov–Bohm(AB) effect was observed in a nanowire-based nanodevice, suggesting the existence of surface states in Bi_2Se_3 nanowires. Bi_2Se_3, as a three-dimensional topological insulator, has been attracted worldwide attention for its unique surface states which are protected by time-reversal symmetry. Here we report the synthesis and characterization of high-quality singlecrystalline Bi_2Se_3 nanowires. Bi_2Se_3 nanowires were synthesized by chemical vapor The structure and morphology were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy In magnetotransport measurements, the Aharonov-Bohm (AB) effect was observed in a nanowire-based nanodevice, suggesting the existence of surface states in Bi_2Se_3 nanowires.