Extracellular proteomic expressions of two fusant strains were analyzed to observe their abilities to degrade polycyclic aromatic hydrocarbons (PAHs) in the source of drinking water from Yangtze River. The extracellular proteomes for the hybrid strains, Fhhh and Xhhh, and one of their parental strain Phanerochaete chrysosporium were measured by the two-dimensional electrophoresis and MS/MS. The similarity of proteome expression was 34.7% between Fhhh and P. chrysosporium and that was 28.6% between Xhhh and P. chrysosporium. PAHs degeneration performance for Fhhh, Xhhh and the native bacterium NJ2007 was studied by biological activated carbon reactor. The specific degradation rate of Fhhh for PAHs was 3.05 x 10(-5) day(-1) which was significantly higher than that of the NJ2007 and Xhhh (P < 0.05). The results indicate that the fusant strain could not express the same proteome as that of its parental strain but could degrade PAHs in the source water with higher efficiency.