Based on the understanding of the spatial specificity of phytoremediation,aiming at the phenomena of eutrophication and black odor in water storage pond which is an important component of connecting the water system in Guanzhong area in recent years,three common floating-bed plants (canna,calamus,and Siberian iris) were selected to explore their purification effect for the raw water in the water storage pond by outdoor hydroponics test. The test lasted 35 days. The results showed that: (1) At the end of the experiment,the height and root length biomass of the three plants increased significantly,and the growth rate was as follows: canna > calamus > Siberian iris. (2) The average removal rates of TN in water bodies were 56.18%,52.17%,and 60.76%,respectively,which were higher than that of the control group (P<0.05). The average removal rates of TP in water bodies of canna and calamus were 55.42% and 58.32%,which were higher than the control group of 15.57% (P<0.05),but the Siberian iris group was not significantly different from the control group (P>0.05). In addition,canna and calamus could also adjust and improve pH and DO in the water. (3) The average removal rates of NH₃—N in water were 76.98%,65.71%,and 78.94%,respectively. The main removal pathways of NH₃—N in the canna and calamus were plant uptake and nitrification. The main removal route of NH₃—N in the Siberian iris group was mainly ammonia volatilization and nitrification,while the removal rate of NH₃—N in the control group was 60.55%,of which main removal reason was ammonia volatilization. The concentration of NO₃^-—N of plant group and control group increased with time,which was mainly related to the difference of water nitrification reaction and plant absorption efficiency in each experimental group. (4) Among the 3 floating-bed plants,calamus was suitable for the purification of the water of the point source pollution and non-point source pollution. The canna was only suitable for the purification of the water of non-point source,while the Siberian iris had poor purification ability and growth adaptation in both,which was not suitable for promotion as an aquatic floating-bed plant. The research results provide a reference for the selection of floating-bed plants for the restoration of polluted water bodies in water storage pond.