Abstract: Genomic DNA was prepared from Schistosoma mansoni(OZ.A) adult and cercaria,S.mansoni adult (NMRI),S.japonicum adult,and was hybridized to three 32p-labelled probes pSM HCR5,pSM HCR4,pSM 889 after cleavage by restriction endonuclease BamHⅠ,The resulting hybridization banding patterns with pSM HCR4 are significantly different between cercaria and adult of S.mansoni (OZ.A) from 1.6 kb to 2.8 kb except there is a same size 3.0 kb major band.There is a minor band in pSM HCR4 pattern for S.mansoni,which can be identified from S.mansoni adult (OZ.A).Moreover,S.japonicum adult have no 3.0 kb major band in pSM HCR5 pattern,which can be distinguished from S.mansoni.The results showed that there was a drastic change of genomic DNA from cercaria to adult,which maybe related to the adaptation of S.mansoni to extremely different living environment in their life-cycle,and also provides more immediate evidence of existence of dynamic changes in the course of development in S.mansoni.