Bi₂S₃ nanorods were prepared by a facile in-situ thermal sulphuration method using BiOCl nanosheets as precursors. The products were characterised by X-ray diffraction, Raman scattering, Fourier-transform infrared spectroscopy and scanning electron microscopy. The optical properties were measured by ultraviolet-visible spectroscopy and photoluminescence techniques. The photosensitive properties were investigated by the photoelectrochemical method. The Bi₂S₃ sample was of pure orthorhombic phase and composed of nanorods with average diameter of ∼200 nm and length of ∼2 μm. A plausible gas phase growth mechanism was proposed which involved the partly templating of the shape of precursors by transforming BiOCl nanosheets to Bi₂S₃nanorods. The photocurrent of the products under irradiation of solar simulator reached 1.0 μA/cm² without bias voltage which was ten times that of the dark current. The photoelectric measurements clearly demonstrate that the as-prepared Bi₂S₃ nanorods possess excellent photosensitivity with stability and reproducibility, enabling the products suitable for the fabrication of high-performance photodetectors and other optoelectric devices.