Thermoelectric material Bi2Te3 has been successfully synthesized by cathodic electrolysis into porous anodic alumina membranes. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and electron diffraction (ED) results show that the as-synthesized samples are hexagonal Bi2Te3 single-crystal nanowires. The morphologies and structure of the Bi2Te3 nanowires have been characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that the Bi2Te3 nanowire arrays with a high-filling rate and a large area are dense, continuous, and smooth. Energy dispersive spectrometer (EDS) analysis indicates that the atomic ratio of Bi to Te is very close to 2:3 stoichiometry.