Dealt with the growing debth of macmphytes roots.spatial distributions of microorganisms and enzyme in artificial wetland and comparison of removal rates of contaminants in different depths of artificial wetlands.the better purifying space in artificial wetland wastewater treatment system has been discussed.From studies on the artificial wetland with cattail(Typha angustifilia)and rush(Juneus effusus), roots of macmpyhter are distributed mainly over 25cm up surface in wetland, spatial distribution of micro rganisms is as follows.The numbers of 5-10em depth are more than the 20cm depth's and further more thanthe 35cm depth's.The activity of phosphata, glucan de-hydratase and proteinase in surface is higher than 20cm depth's.In winter, the performance of purifying wastewater of the Wetland which deeps 20em shows almost no difference with the wetland which deeps 60cm.It may be deduced that there is a better purlfying space in the upper level of artificial wetland for wastewater treatment.