In　order　to　study　the　performance　and　mechanism　of　phosphorus　adsorption　and　removal　by　amphoteric-cationic　surfactant　compositely　modified　bentonite,　different　proportions　of　dodecyl　dimethyl　sulfobetaine　(DSB)　amphoteric　surfactant　and　cetylpyridinium　bromide　(CPB)　cationic　surfactant　were　used　to　organically　modify　bentonite　to　obtain　DSB+CPB　compositely　modified　bentonite.　In　addition,　bentonite　samples　were　characterized　by　X-ray　diffraction　(XRD),　Fourier　transform　infrared　spectroscopy　(FT-IR),　scanning　electron　microscopy　(SEM),　contact　angle　(CA)　and　thermogravimetric　analysis　(TGA).　The　adsorption　process　was　fitted　by　adsorption　isotherm　models　and　kinetic　equations,　and　the　effects　of　modification　ratio,　pH　and　temperature　on　the　adsorption　were　studied.　The　results　showed　that　DSB　modification　improved　the　adsorption　capacity　of　phosphate　by　bentonite.　When　adding　CPB　for　composite　modification,　the　phosphate　adsorption　capacity　by　DSB　modified　bentonite　could　be　further　promoted,　and　the　adsorption　capacity　increased　with　the　increase　of　modification　ratio.　For　the　0.5DSB　and　1.0DSB　amphoteric　modified　bentonite,　their　optimal　composite　ratios　with　CPB　were　0.5DSB+1.5CPB,　and　the　maximum　adsorption　amounts　were　7.81　times　and　8.19　times　as　much　as　that　of　fresh　bentonite,　respectively.　The　phosphate　adsorption　by　the　compositely　modified　bentonite　fitted　Langmuir　isotherm　model　and　pseudo-secondary　adsorption　kinetics　equation.　The　adsorption　capacity　decreased　with　the　increasing　of　pH.　In　addition,　the　adsorption　was　a　physical　and　chemical　process　with　spontaneous,　endothermic　and　entropy　increase　properties.　This　study　provides　the　therotical　support　for　phosphorus　adsorption　and　removal　by　amphoteric-cationic　surfactant　compositely　modified　bentonite.　©　2020,　Science　Press.　All　right　reserved.