Abstract：A graphite-packed MFC was constructed to investigate anode microbial community firstly in the MFC when using quinoline as fuel. PCR-DGGE analysis showed that microbial community changed with the substrates. Due to the inhibition of quinoline toxic ability, microbial species diversity decreased and the dominating species changed significantly when using quinoline-glucose mixture. Compared to the mixed substrates with glucose, the microbial community changed significantly when the substrate changed to sole quinoline. Furthermore, a new species was found, which had the highest homology (100%) with Pseudomonas sp. DIC5RS. We speculated that this strain played the key role in degradating quinoline when using sole quinoline as the fuel.