The　three　dimensional　structure　of　anti-DON　Scfv　antibody　was　modeled　and　refined　using　homology　modeling　and　molecular　mechanics　methods.　Procheck　and　verify_3D　methods　were　used　to　confirm　the　model＇s　reliability.　The　recognition　and　interaction　between　voitoxin　DON　and　its　Scfv　antibody　were　studied　via　molecular　docking　method.　The　result　indicated　that　DON　located　at　the　active　site　of　chain　VL,　binding　to　VH　by　several　residues　in　their　critical　region,　and　formed　a　hydrogen　bond　with　residue　Pro107.　Molecular　dynamics　simulation　and　MM/GBSA　methods　were　used　to　calculate　the　binding　free　energy　between　DON　and　its　Scfv.　The　calculated　binding　free　energy　agreed　with　experimental　index.　It　was　also　indicated　that　the　formation　of　this　complex　was　mainly　driven　by　the　hydrophobic　interaction.　Hydrogen　bond　analysis　and　energy　decomposition　showed　that　Pro107　was　the　most　important　residue　which　contributed　a　stable　hydrogen　bond　and　strong　van　der　Waals＇　interaction.　This　research　provides　some　important　clues　for　structure　design　of　anti-DON　Scfv　antibody,　and　useful　theoretical　instruction　for　the　study　and　development　of　new　types　Scfv　of　toxin-like　small　molecules.