Abstract: In order to clarify the control efficacy of tea saponin against Achatina fulica, the killing effects of tea saponin at concentrations of 0.25%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% were determined by using a laboratory spray method, with distilled water as the blank control and 6% metaldehyde granules as the positive control. The results showed that the molluscicidal effect of tea saponin against Achatina fulica increased with the increasing treatment concentration and prolonged treatment time. At 72 h, as the concentration of tea saponin increased from 0.25% to 2.5%, the corrected mortality increased from 26.7% to 93.1%, which was comparable to that of the positive control group (6% metaldehyde), and there was no significant difference between the two groups. The virulence assessment based on the Probit model revealed that the LC₅₀ decreased significantly with the prolongation of treatment time, with the values of 2.69%, 1.16%, and 0.65% at 24 h, 48 h and 72 h, respectively. The 72 h dose-response curve fitted by the Probit model exhibited a standard sigmoidal shape, with the LC₅₀ located in the rapidly ascending segment and showing good goodness-of-fit. In summary, tea saponin had the potential to be developed as a plant-derived molluscicide for the control of Achatina fulica.