Abstract: Objective To analyze differentially expressed proteins of pairing adult Schistosoma japonicum treated with praziquantel so as to further explore the action mechanism of praziquantel（PZQ）. Methods Pairing adult worms were collected and exposed to PZQ（30 μg/ml） for 18 h with dimethyl sulfoxide（DMSO）treatment as control. The total protein was extracted. Proteins from two groups were identified by two-dimensional-nano-liquid chromatography coupled by tandem mass spectrometry（2D-nano-LC-MS/MS）. Query in database was made to confirm functions of the proteins. Differentially expressed proteins were analyzed statistically. Results There were 12 proteins up-regulated and 4 proteins down-regulated in the treated group compared with the untreated. Ten of the 12 up-regulated proteins were with known function， respectively ascribed to myosin，actin，paramyosin，tropomyosin，tubulin，annexin，stress response HSP70，HSP60 and thioredoxin perioxidase， signal transaction molecule 14-3-3. The down-regulated proteins were molecules with translational/transcriptional regulation，such as polyprotein and myelin gene expression factor. Conclusion There is a significant difference in proteomics between the PZQ-treated and untreated worms， suggesting that PZQ can increase or inhabit the expression of specific genes in adult Schistosoma japonicum.

Key words: Schistosoma japonicum, Praziquantel, Proteomics