This　article　thoroughly　summarized　pollutant　diffusion　pathways　of　contaminated　dredged　material　on　mud　dumping　site,　and　introduced　control　techniques　in　domestic　China　and　out　side　China　as　well.　Full-scale　experiments　of　contaminant　diffusion　control　had　been　done　on　the　mud　dumping　site　of　Taihu　Wuli　lake　environmental　dredging　project,　by　using　the　clay　around　Taihu　lake　as　leachate　prevention　material.　Water　quality　of　five　points　around　the　mud　dumping　site　were　stable　during　the　dredging　process,　which　showed　that　the　clay　around　Taihu　lake　could　be　used　as　leachate　prevention　material.　Flocculants　were　added　to　the　sludge　pipe,　in　which　flocculants　were　mixed　rapidly,　then　they　flocculated　and　sedimentated　on　the　mud　dumping　site.　Or,　the　flocculants　were　added　into　the　discharge　outlet　of　the　mud　dumping　site,　which　mixed　quickly　in　the　clapboard　tank　and　flocculated　in　the　reciprocal　baffled　flocculating　tank,　then　they　sedimentated　in　the　horizontal　flow　sedimentation　tank.　The　results　show　that　the　solid　suspension　concentration　of　effluent　is　less　than　ρ(SS)＜200　mg/L.