Abstract: Three kinds of hydrophytes, Veliveria zizanioides (L.) Nash, Eichhornia crassipes, and Oenanthe javanica DC. were used to investigate enrichment ability of nitrogen and phosphor at the different TN levels with TP constant. It revealed the absorption ability of aquatic plants and purification ability of aquatic macrophytes-rhizosphere microorganisms system respectively in aquatic macrophytes-microorganism system for water purification. It analysed the corresponding number of microorganisms quantitatively. The results shows that these three kinds of aquatic plants had different abilities in removing TN and TP. It also shows that different plants had different optimal treatments, but they could promote the growth of rhizobacteria. In comparison, Oenanthe javanica DC system. had high absorptive capacity in high concentrations of TN, while Eichhornia crassipes system had high absorptive capacity in high concentrations of TP.