Microbial fuel cell (MFC) wes enriched using sludge in wastewater treatment. The microbial community of activated sludge and enriched MFC were analyzed by FISH (fluorescent in situ hybridization) and 16S rDNA sequencing. Bacteroidetes group were pre-dominant in activated sludge by FISH. ${alpha}$ group, ${gamma}$ group and Acintobacter group were dominant and they were similar to distribution. The average value of 10 peak of MFC is 0.44C. When MFC wase enriched by sludge, ${gamma}$-Proteobacteria, Plantomycetes group increased 70% and 60%, respectively. In results of 16S rDNA sequencing, Sphiringomonas sp. was comprised in ${alpha}$ proteobacteria and Enterobacter sp., Klebsiella sp., Acinetobacter sp., Bacillus sp. were comprised in ${gamma}$ proteobacteria and Chryseobacterium sp. was comprised in Flavobacteria were isolated from sludge.