It is study that graft modification of waste newspaper pulp fiber. Grafting rate of waste newsprint pulp increases with increasing initiator dosage, DADMAC dosage, reaction temperature and pulp consistency. When those conditions reach a certain value, grafting rate will lower, but the reducing speed is different. The optimal conditions of waste newsprint pulp modification is the initiator dosage is 8%, mole rate of cationic monomer in total monomers is 60%, reaction temperature is 50°C and reaction time is 2h. Grafting rate of waste newsprint pulp is 15.89% under these conditions.