Abstract:As an important semiconductor, cadmium sulfide nanoparticles (CdS NPs) have outstanding photoelectric properties, adjustable band gap and chemical stability, and have a great application potential in related fields, such as:analytical chemistry, biomedicine, fluorescence imaging and biosensor. The biosynthesis of CdS NPs has been widely studied due to its controllable, low-cost and environmental friendly advantages. However, as a kind of nano-scaled metal sulfide materials, CdS NPs have severe toxic effects on prokaryotic microorganisms. This review summarized the research progress of the toxic mechanism of CdS NPs in prokaryotic cells, including the biosynthetic process of CdS NPs; the toxic effects of CdS NPs on E. coli cells and the defense mechanisms of the cells. Moreover, we discussed the toxic effects of different forms of cadmium on the biosynthetic cells during the CdS NPs biosynthetic process and the unique mechanisms of the NPs biosynthesis strains to respond to the cadmium stress. The purpose of this article is to evaluate the toxicity of CdS NPs on the bacteria cells in a more comprehensive way and to promote the application of the CdS-resistant prokaryotes in related fields.