Uniform single-crystalline bismuth sulfide nanowires were prepared via a convenient solvothermal route under mixed-solvent condition. The nanowires were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectrometry and UV-vis spectrophotometer. The growth mechanism of the one-dimensional nanostructures was discussed. The optical absorption band gap of the nanowires is about 1.7 eV, and the blue-shift phenomenon can be observed with respect of that of the bulk Bi2S3, which might bring in new types of applications.