Photoelectrochemical (PEC) sensor and biosensor are regarded as a hot spot of detection methods which present great potential for future analytical field for various targets. The impetus for the development of Bi₂S₃-based PEC sensor and biosensor was located the adjustable energy band with various morphologies. In this review, we have discussed the Bi₂S₃ semiconductor applied in PEC platform for sensing various target molecules. Due to the high recombination efficiency of the photogenerated electron-hole pairs, various strategies have been employed to improve the migration rate of the photogenerated electron, increase the detachment of photogenerated electron-hole pairs and promote the PEC response of Bi₂S₃, such as element-doping Bi₂S₃, conductive material modified Bi₂S₃, Bi₂S₃-based binary heterojunction, and Bi₂S₃-based multiple heterojunction, which have been discussed in this work. The challenges against Bi₂S₃-based PEC and its future prospects will also be explored.