The effect of polystyrene sulfonic acid (PSSA) macromolecules on the polymerization of acrylamide (AM) has been studied. It was found that the rates of polymerization of AM were greatly increased in the presence of PSSA in the polymerization system.The maximum value of the rate of polymerization of AM was obtained when the ratio of [—SO3H]: [AM] reached 3:1. When the insoluble crosslinked PSSA was used instead of the soluble one, this effect decreased considerably. The interaction between molecules of PSSA and AM was determined by infrared spectroscopy,elementary analysis and X-ray photoelectron spectroscopy.The combination form,-SO3-NH3+CO-,formed between sulfonic group and amide group was found to be existed since the infrared absorption band of -NH2 shifted from 3400cm-1 to 3150cm-1,the binding energy of electron N1s changed from 399.7eV to 401.3 eV,and the atomic ratio of N to S of the products was similar to the ratio of reagents.Based on these experimental results,the mechanism of AM polymerization in the presence of PSSA is proposed.The initial step is the combination of AM with sulfonic group to form—CONHa+,then followed by poly merization on the PSSA macromolecule.The role of PSSA on the polymerization of AM is discussed.