Calcium　carbonate　was　prepared　with　urea　hydrolytic　method,　and　was　characterized　by　Scanning　electron　microscopy　(SEM),　Fourier　transform　infrared　spectroscopy　(FTIR),　X-ray　diffract　meter　(XRD)　and　Ratio　of　surface　area　porosity　analyzer.　It　is　revealed　that　the　Calcium　carbonate　obtained　here　is　aragonite　calcium　carbonate　crystals.　The　adsorption　of　Cd　(II)　ion　onto　aragonite　calcium　carbonate　crystals　were　studied　via　investigating　parameters　as　effect　of　contact　time,　dosage　of　aragonite　calcium　carbonate　crystals　and　initial　heavy　metal　concentration　using　static　batch　adsorption　experiments.　The　results　reveal　that　the　removal　rate　of　Cd　(II)　ion　is　83%　under　the　following　conditions:　temperature　as　25　degrees　C,　contact　time　as　120　min,　initial　concentration　of　the　Cd　(II)　ion　as　100　mg/L,　and　dosage　of　aragonite　calcium　carbonate　crystals　as　0.6　g/L.　The　adsorption　capacity　reaches　200　mg/g.　Meanwhile　the　results　suggest　that　the　adsorption　of　the　Cd　(II)　ion　by　the　aragonite　calcium　carbonate　crystals　well　follows　the　pseudo-second-order　kinetics　model,　and　the　Langmuir　isotherm　model　provides　a　good　fit　to　the　experimental　data.