An alternative two-step method has been proposed for the synthesis of Bi 2 O 3 nanowires with a diameter of about 40nm from common and cost-effective Bi(NO 3 ) 3 ·5H 2 O, Na 2 SO 4 , and NaOH. That is, first, Bi 2 O(OH)SO 4 nanowires were prepared through the precipitation reaction of Bi(NO 3 ) 3 ·5H 2 O and Na 2 SO 4 in distilled water under the ambient condition and second, monoclinic phase Bi 2 O 3 nanowires were prepared via the hydrothermal reaction of Bi 2 O(OH)SO 4 and NaOH at 120°C for 12h. The resultant products were characterized by X-ray diffraction, field emission scanning electron microscope, and high resolution transmission electron microscopy. In addition, the photocatalytic studies indicated that the as-synthesized Bi 2 O 3 nanowires were a kind of promising photocatalyst in remediation of water polluted by some chemically stable azo dyes.