Abstract: More attention is paid to the application of anionic trash catchers in the waste news pulp,this paper compares with alum and polyaluminum chloride(PAC),and analyzes the effects for polyethyleneimine and modified polyethyleneimine on the retention,drainage.The effects indicate that polyethyleneimine and modified polyethyleneimine are better than alum and polyaluminum chloride(PAC)on the retention of the anionic trash.Polyethyleneimine and modified polyethyleneimine can improve the retention of anionic trash and the dewatering speed of the stock,but decrease the paper brightness and strength;The pH changing has little effect on the retention property of polyethyleneimine.Under the neutral condition,polyethyleneimine also has a good retention effect compared with the other synthetic,water soluable organic polymers,natural and inorganic retention aids,polyethylenimine and their derivations have not only higher charge density and lower molar mass,but also lower viscosities.They are easy to handle and readily miscible with water.They can intensively absorb anionic trash,decrease other chemicals addition and white water concentration.It is very important for the clean production of paper industry.