Abstract: Procambarus clarkii has invaded many provinces in China, such as Jiangsu, Hubei, and Anhui. In order to evaluate its effect on Rana limnocharis, we investigated the population density of P. clarkii and R. limnocharis in their natural habitat in Guilin between May and June in 2006. As a comparison, we also car-ried out indoor experiments to study P. clarkii predation on the tadpole of R. limnocharis and Microhyla or-nata. The field investigation showed that there was a significantly negative correlation between the density of P. clarkii and that of R. limnocharis tadpoles, while indoor experiments showed that the number of R. limno-charis tadpoles preyed by Procambarus clarkii was positively correlated with P. clarkii’s body length, and more R. limnocharis tadpoles were preyed than M. ornata tadpoles. Our results suggest that P. clarkii is likely to endanger amphibian larva, therefore, it should be monitored and controlled.