Limits about the traditional flocculants and the superiorities about the microbial flocculants in the water treatment have been reviewed from the effect of wastewater treatment,poisonous to the biology,with or without the second pollution and other aspects. It is analyzed that microbial flocculants will probably replace all or partly the traditional inorganic and organic compound macromolecule flocculants. Lots of optimizing projects were brought forward about how to low the wastewater treatment running cost and how to improve the treatment efficiency. At the same time, lots of examples of the wastewater treatment have been listed to show the microbial flocculants' superiority and the development trends in the future.