[Objective] The interaction of plants on the removals of N and P efficiency by ecological floating bed was studied to provide a theoretical basis for the large-scale construction of Nanhai Lake wetland in the later period.[Methods] Under the condition of natural open water, three kinds of water-stained plants, Scirpus validus, Lythrum salicaria, and Cyperus alternifolius, which are suitable for growth in the north, were selected as floating bed plants, and high-density polyethylene hollow plastic substrates were used as plant carriers, to establish two kinds of floating bed systems of single planting and mixed planting in the Nanhai Lake Wetland Reserve for 90 days of water treatment to study plant growth characteristics and floating bed purification effects.[Results] At the time of harvest in October, the number of tillers of Scirpus validus and Cyperus alternifolius in the mixed floating bed reached 26 and 30, respectively, and the biomasses (fresh weight) were 1.43 kg/plant and 1.98 kg/plant, respectively. The cumulative amount of Scirpus validus grass floating bed N was the best, reaching 110.6 g/m², and the water body TN removal rate was 34.9%. The cumulative amount of mixed floating bed P was the best, reaching 26.02 g/m², and the water body TP removal rate was 43.3%.[Conclusion] The interaction of plants can promote the tillering of plants, but it does not change the N and P absorption capacity of plants. The accumulations of N and P in plants were greatly affected by biomass, and the individual accumulations for the three plants in mixed floating bed were greater than those in single floating bed. The mixed floating bed can be used as a floating bed for the restoration of eutrophic water in Nanhai Lake.