Objective To understand the molluscicidal effects of water extract of Ginkgo biloba's peel on Oncomelania hupensis Methods Immersion methods with a series of six concentrations from 0.3 percent to 3 percent were used to determine the molluscicidal effect. Results The LC 50 of the water extract of 1.0 percent was 28.8 mg/L for 24 hours immersion,12.6 mg/L for 48 hours,and 0.48 mg/L for 72 hours, respectively. The LC 50 of the extract of 2 percent was 19.9 mg/L for 24 hours,11.2 mg/L for 48 hours and 0.48 mg/L for 72 hours,respectively.The LC 50 of the extract of 3 percent was 19.1 mg/L for 24 hours,10.9 mg/L for 48 hours and 0.48 mg/L for 72 hours,respectively. The higher of the concentration, the better of the effect. Meantime, it's poisoning to crops and fishes was very low. Conclusion Ginkgo biloba's peel has molluscicidal effect. It is a good candidate of potential plant molluscicides.