Poly(amidoamine)(PAMAM) dendrimer was used to treat printing ink wastewater,the effects of the generations and the dosage of the dendrimer,the pH value of the solution on the removal rates of chroma and COD were studied.The results showed that poly(amidoamine) dendrimer had good effects in treatment of printing ink wastewater,when the pH value was 5.0,the dosage of poly(amidoamine) was 20 mg /L,the removal rates of chroma and COD were 98.6% and 98.3% respectively.