Abstract: Based upon the biogeographical characteristics and the coevolutionary relationship between plants and animals, I divided the aquatic plants in the northeast China into five districts. Since fish and mollusca are closely associated with aquatic plants, the characteristic species, which are the combination of the indicative diagnostiec species of aquatic plants, fish and mollusca. were used as the bases for such a classification, and the effect of climatic factors on the distribution of living organisms and the effect of geomorphic features on the composition of hydrographic net system were also considered. The major characteristics of the species comosition in each district was discussed.