Macrophyte roots play a crucial role in the functioning of the wastewater treatment constructed wetlands. A review is made on the researches on macrophyte roots in the constructed wetlands, although such researches have not been paid enough attention to and limited literature is available at the present stage. Emphases are put on distribution, growth and biomass, oxygen release of the roots, microbial diversity in the rhizosphere, and decontamination effect correlated with the above characteristics. Suggestions on the researches in the coming years are also put forward.