Abstract: The sulfonated lignin-based chain transfer agent(SL-CTA) was synthesized using pre-sulfonated corn stover lignin, followed by the functional modification of xanthate carbon disulfide and methyl bromoacetate. The SL-CTA was used in the aqueous RAFT polymerization of acrylamide to prepare sulfonated lignin-acrylamide copolymer(SL-g-PAM). Various methods were used to characterize the chain transfer agents and copolymers. The results showed that the arylsulfonation modification was more effective than the sulfomethylation modification. The best modification effect was achieved when 1g of lignin was reacted with 2 g of chlorosulfonic acid at 25 ℃ for 4 h, where the S concentration in sulfonated lignin was 1.83%, the ratio of M_w/M_n was 1.19, the amount of total hydroxyl groups was 4.86 mmol/g, and the water solubility was good. The chemical structure of the SL-CTA was then investigated by FT-IR and ¹³C NMR. The results showed that the stretching vibration absorption peak of C—S bond at 900 cm^-1 and the characteristic peak at 1 738 cm^-1 relating to C=O group were found in the FT-IR spectrum, and the peak at δ 172 corresponding to carbon atom of the C=S appeared in the ¹³C NMR spectrum, proving the successful synthesis of the chain transfer agent. In addition, the effects of the ratios of monomer/chain transfer agent/initiator, pH value and reaction temperature on the monomer conversion in the aqueous RAFT polymerization system of acrylamide were investigated. The results showed that the conversion rate was as high as 98.5% when the ratio of monomer/chain transfer agent/initiator was 500∶4∶1, pH value was 5, reaction temperature was 70 ℃ and reaction time was 4 h. Under the experimental conditions, the first-order kinetic curve of the polymerization reaction showed a good linear relationship, and the relative molecular mass of the obtained polymer also presented a linear relationship with the monomer conversion rate. At the same time, its polydispersity index was low and the distribution was relatively narrow(1.13-1.43), which all indicated that the reaction had high controllability.