Two types of microbial fuel cells (MFCs) were adopted to analyze the effects of exoelectrogens and electron acceptors on the electrogenesis performance of MFCs. One was conventional MFCs inoculated with sewage and using nitrate as electron acceptor (S-MFCs), and the other one was modified MFCs inoculated with anaerobic treated wastewater and using ferricyanide as electron acceptor (A-MFCs). Exoelectrogens and electron acceptors had substantial effects on the acclimation period and the power output period of MFCs. The acclimation period was reduced from 500 h for S-MFCs to 430 h for A-MFCs, and the power output period was prolonged from 100 h for S-MFCs to 350 h for A-MFCs. The modified MFCs increased the removal of COD and the output of voltage by 25% and 300%, respectively. To select appropriate exoelectrogens and electron acceptors were crucial to the improvement of MFCs performance.