Being the key component of aquatic ecosystem, the aquatic macrophyte is a natural carrier of biofilm. The restoration of aquatic macrophyte contributes to the increase of water area of biofilm. Compared with the nonbiological medium, there were a complex interaction mechanism between the aquatic macrophyte and the microbe. On one hand, aquatic macrophyte provide the attachment sites and nutrients for the microbe, and the allelochemicals emerged from the aquatic macrophyte have an effect on the types and quantity of attached microbe; on the other hand, the attached microbe can promote or restrain the growth of aquatic macrophyte. Additionally, flow and water quality can have important effects on the formation, structure and the composition of community of aquatic macrophyte and biofilm. As a complex interaction system, aquatic macrophyte and biofilm is the fundamental unit of water ecosystem. The study on the characteristics of plant surfacesurface biofilm system and its role on the transformation of carbon, nitrogen and other elements in water, and the pollutants removal mechanism should be one of the directions of water ecological research in the future.