Chestnut blight fungus Cryphonectria parasitica and hypovirus constitute a model system to study fungal pathogenesis and host-virus interaction. Proteomic analysis of chestnut blight fungus upon hypovirus infection was conducted to find the differentially expressed host proteins.According to the characteristics of this filamentous fungus, an optimized extraction protocol for fungal total protein was developed. Two-dimensional electrophoresis (2-DE) was used for comparative proteomic analysis of wild strain EP155 and hypovirus-infected strain EP713. The quantitative RT-PCR was applied to analyze mRNA expression level of protein-coding genes.In total 71 protein spots were detected to be differentially expressed on the base of EP155 of which 19 up-regulated and 52 down-regulated. Fifty-eight unique proteins were identified by mass spectrometry. Further study on quantitative RT-PCR indicated that the regulation of related host genes by hypovirus occurred at different levels.The TCA cycle of C. parasitica was weakened after hypovirus infection and the process of methylation was regulated by hypovirus. Meanwhile, viral regulation of virulence factors also contributed to the phenomenon of hypovirulence.