Abstract: A β-cyclodextrin (β-CD) based cationic flocculant P(β-CD-MAH-co-DMC) was synthesized by means of aqueous solution polymerization, in which the potassium persulfate and sodium sulfite were used as the initiators, and the derivative of β-CD (β-CD-MAH) modified by malefic anhydride and methyl acryloyloxyethyl trimethyl ammonium chloride (DMC) were used as monomers. The chemical structure and properties of P(β-CD-MAH-co-DMC) were characterized through test methods of FT-IR, intrinsic viscosity, cationic degree and so on. The results of decolorization experiment showed that using compound flocculants made up of P(β-CD-MAH-co-DMC) and anionic flocculant called Polymer X mainly including sodium alginate had a better effect on dealing with Acid Blue 324 dye solutions than using P(β-CD-MAH-co-DMC) alone, and the compound flocculant had higher decolorization rate and faster decolorization speed for the dye solution, and its’ anti-salt and alkali resistance properties were more excellent.