Abstract: The nonradioactive labelled probe pSM889 was hybridized to Southern blots of genomic DNA of five isolates of Schistosama japonicum from Anhui, Hubei, Guangxi, Sichuan and Yunnan in the mainland of China. The major bands of hybridization of DNA digested by restriction endonucleases EcoRI and BamHI are same among the five isolates, but the minor bands of hybridization of DNA digested by EcoRI show some differences between 4. 4-9. 6 kb and between 2. 3-4. 4 kb among the five isolates. The result shows that the five isolates are of some genetic variation. It provides, at molecular level, evidence of the existence of different strains of 5. japonicum in the mainland of China.