Abstract: Fermentation conditions of a rhizospheric strain named as SL-30 from Phytolacca acinosa Roxb. were optimized. On the basis of early study, Plackett-Burman design was undertaken to evaluate the effects of the eight factors and three statistically significant parameters including soluble starch, peptone and initial pH were selected. Then a response surface methodology was used to optimize the above three factors, and to find out the optimal concentration levels and the relationships between each pair of these factors. The result showed, under conditions of soluble starch 16.40 g/L, peptone 3.76 g/L and initial pH 3 the molluscicidal activity of fermentation broth’s filtrate reached 98.949%. After six batches cultivation, the predicted values were verified by validation experiments.