Background:　Cancer　metastasis　caused　by　circulating　tumor　cells　(CTCs)　accounts　for　90%　cancer-related　death　worldwide.　Blocking　the　circulation　of　CTCs　in　bloodstream　and　their　hetero-adhesion　to　vascular　endothelia　of　the　distant　metastatic　organs　may　prevent　cancer　metastasis.　Nanomaterial-based　intervention　with　adhesion　between　CTCs　and　endothelia　has　not　been　reported.　Driven　by　the　novel　idea　that　multivalent　conjugation　of　EpCAM　and　Slex　antibodies　to　dendrimer　surface　may　enhance　the　capacity　and　specificity　of　the　nanomaterial　conjugates　for　capturing　and　down-regulating　colorectal　CTCs,　we　conjugated　the　dendrimer　nanomaterial　with　the　EpCAM　and　Slex　antibodies,　and　examined　the　capacity　of　the　dual　antibody-coated　nanomaterial　for　their　roles　in　interrupting　CTCs-related　cancer　metastasis.　Results:　The　antibody-coated　nanomaterial　was　synthesized　and　characterized.　The　conjugates　specifically　bound　and　captured　colon　cancer　cells　SW620.　The　conjugate　inhibited　the　cells＇　viability　and　their　adhesion　to　fibronectin　(Fn)-coated　substrate　or　human　umbilical　vein　endothelial　cells　(HUVECs)　in　a　concentration-dependent　manner.　In　comparison　with　SW480　and　LoVo　cell　lines,　the　activity　and　adhesion　of　SW620　to　Fn-coated　substrate　and　HUVECs　were　more　specifically　inhibited　by　the　dual　antibody　conjugate　because　of　the　higher　levels　of　EpCAM　and　Slex　on　SW620　cell　surface.　The　hetero-adhesion　between　SW620　and　Fn-coated　substrate,　or　HUVECs　was　inhibited　by　about　60-70%.　The　dual　conjugate　showed　the　inhibition　capacity　more　significant　than　its　corresponding　single　antibody　conjugates.　Conclusions:　The　present　study　provides　the　new　evidence　that　coating　nanomaterials　with　more　than　one　antibody　against　CTCs　may　effectively　interfere　with　the　interaction　between　SW620　and　HUVECs.