Abstract: To investigate whether Aeromonas hydrophila generally mediate liver protein expression, isobaric tags for relative and absolute quantitation (iTRAQ) combined with LC-MS/MS were used to screen liver proteins of black carp Mylopharyngodon piceus after infected with Aeromonas hydrophila (BCK0712) for 24 hours. Differentially expressed proteins were screened through identification and quantification analysis. As a result, a total of 4475 proteins were identified and 188 differentially expressed proteins were quantified upon bacterial infection, including 70 up-regulated and 118 down-regulated proteins. Bioinformatics analysis indicated that these differentially expressed proteins were mainly associated with complement and coagulation cascades, spliceosome, endocytosis, oxidative phosphorylation, carbon metabolism, arginine and proline metabolism, etc. Hispathological characteristics including unclear cell boundary, hemorrhage at different degrees and necrosis were observed on liver of black carp infected with A. hydrophila under microscope after hematoxylin-eosin staining. The potential mechanism of regulated proteins by A. hydrophila infection in liver pathology need further investigation.