A　unique　bouquet-like　calcium　sulfate　dihydrate　(BCSD)　was　successfully　synthesized　from　calcium　chloride　and　aluminum　potassium　sulfate　in　aqueous　sodium　carboxymethyl　cellulose　(CMC)　solution　by　means　of　a　metathesis　reaction.　The　morphology　and　structure　of　BCSD　were　characterized　by　scanning　electron　microscopy,　powder　X-ray　diffraction　and　transmission　electron　microscopy.　The　adsorption　of　different　organic　dyes　from　aqueous　solutions　onto　the　as-synthesized　BCSD　was　then　investigated,　taking　into　account　the　influences　of　adsorbent　dose　(1.0-3.5　g　L-1),　solution　pH　(5.0-12.0)　and　adsorption　time.　The　results　indicated　that　the　temperature　and　agitation　rate　had　no　effect　on　the　morphology　of　the　samples.　With　the　increase　of　CMC　concentration　from　0.10%　to　0.50%,　lamellar　calcium　sulfate　dihydrate　(LCSD)　gradually　transformed　into　rod-like　calcium　sulfate　dihydrate　(RCSD),　and　eventually　generated　BCSD.　The　as-prepared　BCSD　was　monoclinic　with　preferential　[021]　and　[041]　orientations.　Moreover,　BCSD　selectively　adsorbed　Congo　red　(CR)　instead　of　rhodamine　B　and　methyl　orange.　The　adsorption　equilibrium　process　of　CR　was　an　exothermic　process　and　could　adequately　be　described　by　the　Langmuir　isotherm　model.　The　calculated　maximum　adsorption　quantity　(q(max))　was　1224.09　mg　g(-1)　at　303.5　K,　which　was　almost　12　times　larger　than　that　onto　LCSD　(100.80　mg　g(-1)).　Additionally,　the　adsorption　process　of　CR　was　a　multi-step　process,　and　the　adsorption　kinetics　could　be　described　in　terms　of　a　pseudo-second-order　model.　From　attenuated　total　reflectance　Fourier　transform　infrared　spectroscopy　and　X-ray　photoelectron　spectroscopy　studies　it　was　concluded　that　CR　was　chemisorbed　on　BCSD.　These　results　indicate　that　BCSD　is　a　promising　candidate　in　wastewater　treatment.