Conventional　dissolved　air　flotation　(DAF)　has　the　problems　of　low　efficiency　for　microbubble　meshing　and　particle　adhesion,　and　unstability　of　the　adhesion　between　microbubbles　and　particles.　In　this　work,　a　novel　countercurrent-cocurrent　dissolved　air　flotation　(CCDAF)　was　developed,　of　which　the　contact　room　was　consisted　of　collision　and　adhesion　contact　room,　and　each　room　was　introduced　dissolved　air　water.　The　results　showed　that　the　CCDAF　significantly　enhanced　the　adhesion　efficiency　of　microbubbles-floc.　The　average　removal　efficiency　of　turbidity　and　algae　were　96.4%　and　96.50%,　respectively.　The　diameter　of　particles　for　effluent　was　mainly　ranged　in　2-7　μm.　Most　of　the　removed　substance　was　macromolecules　and　hydrophobic　organic　compounds.　CODMn,　UV254,　DOC　had　achieved　37.6%,　46.3%　and　32.11%,　respectively,　indicating　the　significantly　higher　removal　efficiency　of　CCDAF　than　the　traditional　DAF.　The　analysis　of　the　removal　mechanism　between　microbubbles　and　particles　showed　that　the　collision,　adhesion　and　copolymerization　in　countercurrent　room　and　collision,　adhesion,　wrapped,　meshing　and　adsorption-bridging　in　cocurrent-contact　room　were　probably　the　reasons　to　enhance　the　removal　efficiency　of　this　CCDAF.　©　All　Right　Reserved.