The　landscape　water　body＇s　eutrophication　tendency　is　one　of　the　main　issues　of　recycled　water　reuses　to　urban　water　systems　needs　to　be　resolved.　The　allelopathy　of　aquatic　plants　which　can　inhibit　the　excessive　breeding　of　algae　is　a　new　water　quality　control　technology　which　is　low-carbon　and　green　technology　compared　with　the　traditional　physical　and　chemical　methods.　This　process　doesn＇t　need　dosing　potions,　and　no　energy　consumption　needed.　For　less　damage　to　the　environment,　it　could　get　integrated　benefits　both　for　water　quality　environment　and　socio-economic.　This　experiment　mainly　discusses　the　inhibitory　effect　of　two　kinds　of　Submerged　plants　(　Ceratophyllum　demersum　L　,　Hydrilla　verticillata　)　to　Chlorella　pyrenoidosa　Chick　and　Scenedesmus　oblipuus　which　are　dominant　species　in　the　landscape　water　body　of　Beijing,　in　the　condition　of　co-culture.　Choosing　the　content　of　algal　cell＇s　chlorophyll　A,　the　color　of　the　solution,　and　the　number　of　algal　cells　as　indicators,　the　changed　situations　of　algae　growth　in　the　process　of　co-culture　are　analysis.　The　results　could　be　used　to　provide　an　experimental　basis　for　the　technology　of　allelopathy　on　the　growth　of　algae　control.　©　2011　IEEE.