To　restrain　the　nano　zero-valent　iron　(NZVI)　in　aqueous　solution　from　being　reunited　and　oxidized,　this　paper　used　sodium　carboxymethyl　starch　(CMS),　which　is　an　environmentally　friendly　and　cheap　material,　for　coating　and　surface　modification　of　NZVI　so　as　to　improve　its　dispersity　and　suspension　property.　Transmission　Electron　Microscope　(TEM)　and　X-ray　diffraction　(XRD)　were　used　to　study　the　microstructure　and　components　of　the　modified　NZVI,　and　the　2,　4-dichlorophenol　2,　4-(DCP)　removal　efficiency　was　researched　through　chemical　experiment.　Experiments　showed　that　the　modified　NZVI　was　about　80~100　nm　in　diameter,　present　as　chain　or　dispersed　particles.　The　main　component　was　zero-valent　iron,　and　it　had　strong　reducibility.　When　the　proportion　of　CMS　was　80.00%,　the　suspension　property　was　the　best;　The　NZVI　after　CMS　coating　and　surface　modification　retained　the　original　activity.　In　the　experiment　investigating　the　removal　effect　of　2,　4-DCP　using　different　proportion　of　cladding,　the　same　finding　was　obtained.　When　the　CMS＇s　proportion　was　80%,　the　removal　effect　was　the　best,　reaching　up　to　83.69%,　and　the　dechlorination　and　degradation　were　apparent.　©　2017,　Science　Press.　All　right　reserved.