Abstract: Abstract: In this paper, acrylamide (AM) is used as molecular skeleton, acrylamide ethyl three methyl ammonium chloride (DAC) and dimethyl methacrylate (DMAEMA) are cationic monomers, and a new type of organic polymer material is synthesized by aqueous solution polymerization Cationic flocculant PADD. And determine the optimum reaction conditions for its synthesis: pH=3, polymerization temperature of 30 ℃, reaction monomer mass fraction 25%, initiator sodium sulfate (Na2S4O8) and sodium sulfite (Na2SO3) quality fraction of 0.1%, The dosage ratio of medicament monomer was 40:30:30, and the polymerization time was 6h. Afterwards, the viscosity of the product was determined by viscosity method and the relative molecular mass of the product was calculated, the polymer structure was analyzed and characterized by infrared spectroscopy, and the flocculation and sedimentation of coal slurry in preparation plant was studied by using synthetic flocculant.