Abstract: In this paper, a computerized numerical systensatics was used to analyse the 5 different isolates of Schistosoma japonicum in the mainland of China by means of fuzzy clustering method with 32 quantitative data of each isolate about the morphological and biological cha-racters.A dendrogram of the 5 isolates of S. japonicum was constructed on the basis of simi-larity coefficients as S'hown in Figure 1. The phyJogenetic rektionships revealed by the present study show that the two isolates of Anhui and Hubei get together firstly in one group, then the isolates of both Yunnan and Guangxi gather in another group, while the Sichuan isolate is closely related to the group of Anhui-Hubei isoktes, not to the Yunnan onest although both Sichuan and Yunnan isolates were in the southwest China.