With the advent of the postgenomic era, metaproteomics is gradually emerging as a new tool that has been successfully applied in life sciences and pharmacology, and has become one of the most popular methods in many research fields. Although application of metaproteomics in studying wastewater biotreatment is still in its infancy, its strong potential that contributes to basic research has already been well noticed. This paper reviewed the recent research advances  in using metaproteomics to biotreatment wastewater. It also reviewed and summarized the research strategies and application of metaproteomics, such as the identification of functional proteins or enzymes, understanding of the mechanisms of pollutant biodegradation, deduction of key metabolic pathways, and investigation of microbial ecosystems within different sludge of microbial habitats.