In this paper, the graft terpolymer, which is called Chitosan-based heavy metal capture flocculant CSC-P(AM-AA), of carboxymethyl chitosan (CSC) and acrylamide (AM) and acrylic acid (AA) were successfully prepared by photopolymerization. In order to demonstrate the successful preparation and characterization of the graft copolymer, the IR spectra, XRD, TG-DSC, and scanning electron microscopy (SEM) were used to characterize the product polymer. The results showed that the graft copolymer of CSC-P (AM-AA) was successfully prepared, and the graft copolymer had good soluble ability. In addition, P (AM-AA) had a structural characteristics that were significantly different from those of P(AM-AA), due to the graft polymerization of carboxymethyl chitosan. The flocculation results showed that CSC-P(AM-AA) had good heavy metal removal performance. At pH 8, dosage of 8 mg·L-1, and rotation speed of 150 r·min-1, the optimal removal rate of Cu2+ by CSC-P(AM-AA) was 87.0%.