A　layer　of　manganese　dioxide　/　poly　(p-phenylenediamine)　(PoPD)　complex　was　coated　on　the　surface　of　polyphenylene　sulfide　(PPS).　First,　the　o-phenylenediamine　(OPD)　monomer　was　uniformly　adsorbed　on　the　surface　of　the　PPS　fiber　by　the　effect　of　π-π　conjugation.　Then,　the　o-phenylenediamine　was　oxidized　by　the　potassium　permanganate　solution　to　produce　poly　(p-phenylenediamine)　coat,　while　the　potassium　permanganate　was　reduced　to　MnO2　catalyst　and　inserted　into　the　poly　(o-phenylenediamine)　matrix.　The　MnO2　catalyst　was　firmly　bonded　with　the　PPS　filter　because　the　MnO2　/　PoPD　complex　formed　by　in-situ　polymerization　exhibited　a　strong　bond　with　the　PPS　filter.　The　preparation　method　of　MnO2/PoPD@PPS　composite　filter　was　simple.　Due　to　the　mild　experimental　conditions,　the　performance　of　the　PPS　filter　media　was　not　damaged.　The　structure　and　properties　of　MnO2/　PoPD@PPS　composite　filter　were　studied　in　detail　by　FESEM,　XPS,　XRD,　FT-IR　and　denitrification　test.　The　results　of　denitration　test　show　that　the　denitrification　rate　of　MnO2/PoPD@PPS　composite　filter　increases　with　the　increase　of　KMnO4/PPS　mass　ratio.　The　optimum　denitrification　rate　is　36%-94%　at　80-180　with　the　KMnO4/PPS　mass　ratio　of　11,　and　it　is　88%　at　160　after　10　h　catalyst　stability　test.　The　XPS　spectrum　of　Mn　2p　proves　that　the　catalyst　on　the　composite　filter　is　MnO2　that　possesses　amorphous　structure　observed　from　XRD　patterns.　It　can　be　observed　from　the　FESEM　diagram　that　the　dispersion　of　the　MnO2　catalyst　on　the　PPS　filter　is　uniform.　©　2017,　Science　Press.　All　right　reserved.