Abstract: As the increasing development of modern industry，industrial wastewater discharged into the environment would cause serious harm to human health and the environment． The toxicity of chromium would change with different valence． In the process of microbial metabolism，Cr ( VI ) can be reduced to less soluble Cr ( III ) and the toxicity would be reduced effectively． Several aspects were summarized such as the type of mechanism of microbial Cr ( VI ) reduction，genetic characteristics of related reductase，microorganisms of Cr ( VI ) reduction，factors influencing reduction，problems in the reduction process and the develogment direction．