Metal and metal oxide nanoparticles are widely used in daily life,and will enter into the environment by all kinds of ways,so it is essential to assess their environmental and health risks.Metal and metal oxide nanoparticles have unique physical and chemical properties.Summarized the microbial toxicity studies of metal and metal oxide nanoparticles in the literature,with special attention to their effects on pollution treatments(wastewater treatment,solid waste treatment),then explained the possible toxicity mechanisms.On this basis,it presented the current problems and proposed future research prospects on nanotoxicity.