Select three macrophytes Iris tectorum,Ranunculus sceleratus L.and Rumex acetosa L.cultivating with no soil to study their growth characteristics and their ability to removal main pollutants from domestic wastewater.The experiments went on during late spring to early summer,the results show that the test plants grow well.When the retention time is 7 d,the contribution rates of Iris tectorum on the removal of COD,TP,TN are 46.74%,17.71%,11.33%;while Ranunculus sceleratus are 39.82%,28.59%,8.88%;Rumex acetosa are 54.69%,20.26%,7.47%.After the treatment the quality of wastewater is improved prominently,which indicates that these three macrophytes applied to constructed wetland are feasible.