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 Bi2S3 nanorods. 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.