In this study, to generate bioelectricity to power the monitoring sensors and to improve sediment simultaneously is discussed in Yamaguchi bay located in the south part of the Honshu island, Japan through sediment microbial fuel cell (SMFC). To supply energy to the geoenvironmental monitoring sensors is a serious problem, as traditional batteries and solar cells are often inconvenient due to the limitations of recharging and weather conditions, respectively. Four different sediments were used in the laboratory to generate bioelectricity and to improve sulfide contamination simultaneously by SMFCs. The acid volatile sulfide (AVS) was determined to check the improvement of the geo-environment of the sediments as it was the main source of contamination in the intertidal zone (tidal flat). Various factors which affected the voltage generation have been studied. Voltage values showed almost twice when two anodes were used instead of a single anode. Higher temperature showed the higher voltage due to increased activity of the bacteria in the higher temperature. AVS values reduced quickly when the closed circuit was used. All the marine sediments showed the decreasing trend of AVS value with time and reached at the 0.2 mg/g-dry mud indicating the geoenvironmental improvement of the marine sediments within 14 days . Field test showed the higher value of voltage comparing to the laboratory test by using the similar sized SMFCs.