Low-toxicity single crystal SnS nanowires had been successfully synthesized by the catalystassistant chemical vapor deposition. Au nanoparticles were applied on the ITO surface as the catalysis, using SnS powder and S powder as forerunners. The structure, morphology and optical properties of the prepared SnS nanowires were characterized. The experimental results show the as-synthesized nanowires are single crystalline with a preferential orientation. The synthesized SnS nanowires show strong absorption in the visible and nearinfrared spectral region, and the direct energy band gap of SnS nanowires is 1.46 eV.