Abstract: Polyacrylamide is commonly used as a water-treatment agent in China and abroad, it may bring a potential threat to microorganisms when it is discharged into natural environments. To obtain toxicity information of polyacrylamide (PAM) and acrylamide (AM), the acute and sub-acute tests were conducted with specimens of Eisenia fetida using OECD (Organization for Economic Co-operation and Development) artificial soil in this study. The results showed that LC50 of PAM and AM were more than 2000 and 164.01 mg/kg, respectively, the toxicity of PAM was much lower than AM. There was no significant effect of PAM on the survival and growth of E. fetida in acute and sub-acute toxicity tests; while at the concentration of 100 mg/kg AM, it showed a significant toxicity effect (P<0.05). Earthworm reproduction rate was significantly affected by both PAM and AM (P<0.05). So, polyacrylamide residual in sewage sludge had potential ecological risk.