Abstract: The dominant strain Bacillus cereus LYX03, isolated from the heterotrophic culture of marine benthic microbial fuel cell (MBMFC), and a newly identified marine bacteria Algoriphagus faecimaris LYX05 isolated from the same source, were injected to the surface of anode of MBMFC. The bacterial community compositions and the electricity production efficacy of MBMFC were analyzed by means of bacterial fingerprinting technique denaturing gradient gel electrophoresis, 16 S rDNA sequencing and voltammeter analyses. The effects of glucose and LB medium to the bacterial community compositions and electricity production efficacy were further analyzed. The results indicated that Algoriphagus faecimaris LYX05 and LB medium decreased the electricity production efficacy of MBMFC significantly. While the injections of Bacillus cereus LYX03, extracellular DNA and glucose did not generated significant effects. The injections of two marine bacterial strains and carbon source such as glucose, and LB medium showed a large disturbance of microbial communities of the anodes with decreased bacterial diversity. Chryseobacterium sp. was the most vulnerable species.