Abstract: Cationic polyacrylamide（CPAM） was synthesized using photo-initiation polymerization system by acrylamide（AM） and methacrylatoethyl trimethyl ammonium chloride（DMC）.The cationic degree of the product was 16.03% and the intrinsic viscosity was 548 ml·g^-1.The synthesized cationic polyacrylamide sample was characterized by FT-IR and the flocculation performance was also measured.The results showed that the settling velocity was 39.2cm/min and the transmittance was up to 98.9% while CPAM in dealing with high ash content and fine size coal slime water.The suitable cationic degree of CPAM was 16.03%.The flocculation performance of CPAM was as excellent as French commercial grade CPAM when compared with PAM,HPAM and AmPAM.