Using　tapioca　starch　as　main　material　and　the　self-developed　organic-bentonite　as　modifier,　tapioca　starch/bentonite　composite　binder　was　made　by　melting　and　solution　intercalation　technologies.　The　binder　was　characterized　by　means　of　FTIR,　XRD　and　mechanical　performance　test.　The　results　show　that　this　nanometer　composite　binder　has　not　only　high　bond　strength,　good　humidity　resistance,　and　excellent　collapsibility,　but　also　low　costs,　simple　process　and　environment　friendly　characteristic.