Abstract: Anode is a key factor which limits the power output of benthonic microbial fuel cell,and cell performance can be improved through its modification.Graphite anodes were modified with manganese sulfate redox mediator and the effect of manganese sulfate content on the performance of anode and cell electricity generation was studied.Results showed that manganese ioncould effectively accelerate the electron transfer from the bacteria to anode.When the manganese sulfate content was 4%,the anode performance was best,the battery internal resistance was minimum,and the value of the maximum power output density was 51.64 mW/m²,3 times higher than that of the plain graphite electrode.