Abstract:【Aim】 The invasion of the golden apple snail (Pomacea canaliculata) poses a severe threat to China's wetland and agricultural ecosystems. To ensure national biosecurity, ecological safety, and food security, developing green biological molluscicides is essential for control of this pest. 【Method】 Herein, we obtained an extract of the botanical agent Euphorbia pekinensis using a cold soaking ultrasonic extraction procedure and assessed the toxic effects of this extract on P. canaliculata. In addition, we comprehensively analyzed the mode of action of the extract based on dynamic observations. 【Result】 We found that the ethanol extract of E. pekinensis has notable molluscicidal activity, with snail mortality being observed within 12 h of treatment, and positive correlations being detected among the rate of mortality, extract concentration, and exposure duration. By performing regression analysis based on the probit unit method, we determined the 72-h median lethal concentration (LC50) values of 0.639 and 0.926 g·L-1 for juvenile and adult snails, respectively, thereby indicating the higher sensitivity of juveniles. Treatment using the LC50 of the extract over a 72-h period revealed an initial increase and subsequent decline in the levels of pedal acetylcholinesterase and nitric oxide synthase in snails. After treatment, we detected a significant increase in malondialdehyde content in the snail's liver (P<0.05), along with notable reductions in glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase, compared with the control group. These findings indicate that E. pekinensis extracts can significantly disrupt snail liver function and antioxidant mechanisms. 【Conclusion 】 The findings of this study reveal that an extract of E. pekinensis has significant molluscicidal bioactivity against P. canaliculata, thereby indicating its potential for development as a biological molluscicide.