Abstract: Four dominant marine imperfect fungi of HTTD-Z0901~HTTD-Z0904(labeled as LC1、LC2、LC3 and LC4) were isolated from the sediment in Jiaozhou Bay.After enrichment and cultivation, their capability of PCB180 removal was tested.Effect of PCB180 on the fungi biofilm was also studied.Results indicated that the anaerobic degradation rates of PCB180 by the four dominant marine imperfect fungi ranged between 2.04%~75.63%.Within 1 to 15 days, the anaerobic degradation rate increased with the incubation time before leveling off.The overall degradation rate follows the trend of LC3 LC4 LC2 LC1.Anaerobic degradation rates of PCB180 by LC3 and LC4 were the highest on day 10 with a rate of 75.63% and 49.34% respectively.Whereas the highest degradation rates by LC1 and LC2 were on day 7, which are 8.27% and 19.15% respectively.We also found that different fungi showed varying PCB180 anaerobic degradation rates with LC3 a rate of 75.63% and LC1 a rate of only 8.27%.AFM results showed that fungal conidium had different changes.These changes included the change of spore shape, the lost of original feature, the lost of the characteristic ring structures, and so on.These morphology changes indicated that, to some extent, the fungal biofilms were damaged after the induction of PCB180.These could be the visual evidence of biofilm dependent self protection against PCB180 by the fungi.