Tapioca　starch　was　used　as　the　main　material　and　self-developed　organic-bentonite　used　as　the　modifier　to　make　tapioca　starch/bentonite　composite　binder　by　melting　and　solution　intercalation　technologies.　The　binder　was　characterized　by　means　of　FTIR,　XRD　and　mechanical　performance　test.　The　results　showed　that　the　interlamellar　spacing　of　improved　organic　bentonite　was　larger　than　that　of　organic　bentonite　and　Na-bentonite,　and　the　more　the　interlayer　spacing　of　bentonite,　the　more　advantageous　the　binder　to　the　intercalation　reaction　between　starch　and　bentonite,　leading　to　higher　dry　tensile　strength.　The　nanometer　composite　binder　also　features　high　bond　strength,　good　humidity　resistance,　low　costs　and　simple　process,　and　is　environment-friendly.