Aiming　at　the　problem　of　phosphorus　removal　in　water,　Mg/Al-layered　double　hydroxides　(Mg/Al-LDHs)　were　synthesized　via　optimized　constant　pH　co-precipitation　method,　and　highly　efficient　phosphorus　adsorbent　Mg/Al-layered　double　oxide(Mg/Al-LDO)　was　obtained　when　it　was　calcined　at　high　temperature.　Based　on　the　adsorption　characteristics　of　phosphorus　removal,　the　study　combined　Zeta　potential,　X-ray　diffraction　(XRD)　and　Fourier　transform　infrared　spectroscopy　(FTIR)　to　analyze　the　changes　of　isoelectric　point,　crystal　structure　and　functional　group　before　and　after　adsorption.　In　addition,　Mg/Al-LDO　of　phosphorus　adsorption　mechanism　was　discussed.　The　results　indicated　that　using　the　optimized　co-precipitation　method　in　the　conditions　of　Mg/Al=21,　calcination　temperature　450,　and　calcination　time　2　h,　the　Mg/Al-LDO　adsorption　capacity　of　phosphate　was　the　best,　and　the　maximum　adsorption　capacity　could　reach　176.94　mg·g-1,　which　was　basically　consistent　with　the　theoretical　adsorption　capacity　of　191.57　mg·g-1,　far　higher　than　those　of　Mg/Al-LDHs　and　other　phosphorus　adsorbents.　The　results　showed　that　the　experimental　data　has　the　best　fitting　result　with　pseudo-second-order　kinetics　model.　The　adsorption　process　was　consistent　with　Langmuir　adsorption　isotherm　model.　The　results　of　Zeta　potential,　XRD　and　FTIR　showed　that　phosphorus　adsorption　of　Mg/Al-LDO　was　accomplished　co-operatively　by　electrostatic　attraction,　anion　in　layer,　ions　exchange,　and　surface　co-ordination.　©　2017,　Science　Press.　All　right　reserved.