To investigate the impact of different sludge inoculum on microbial community formation of the anode in microbial fuel cells, single-chamber bottle-shaped microbial fuel cell with air cathode and planar Indium tin oxide glass anode were utilized as the experimental reactors, inoculated by sludge from Chinese and American Sewage wastewater treatment plant separately. The results indicate that the overall operation efficiency of Chinese sludge inoculated reactor is better than that of American sludge inoculated one, which shows shorter start-up time, higher operation voltage, output power density, current density, and COD removal efficiency. There are significant differences in the communities composition of the two reactors, which may be related to the fact that the one sludge is not treated by chlorination/ dechlorination. The diversity of the communities in the sludge from Chinese plant is higher than that from American plant. The communities in the former were distributed mainly in five classes. While the communities in the latter were distributed mainly the 3 classes. Using Indium tin oxide glass as the anode in microbial fuel cells could harvest the whole biofilm to do the high-throughput sequencing, resulting more accurate data to do the following analysis.