The objective of this study was to investigate the feasibility of the novel cationic modified flocculant removing harmful algal cells. The graft between CP and a cationic quaternary ammonium monomer N-(3chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC) was illustrated by using elemental analysis, Fourier-transform infrared (FTIR) and scanning electron microscope (SEM).