<0.01).The contribution of direct N and P uptake to different submerged macrophytes had the ranges of 1.5%-13.3% and 2.2%-13.2%,and the synergism contribution (deducting self-purification capacity of water) of different submerged macrophytes ranged 22.5%-29.9% and 10.1%-20.6%,indicating that the synergistic effect of submerged macrophytes purification was much more significant than the direct uptake effect in the process of water purification.