Abstract: Microbial reduction of iron oxides minerals is an essential component of the biogeochemical cycle of iron. The use of redox active electron shuttles to mediate the transfer of biogenic electrons to minerals and accelerate Fe(III) reduction is an important pathway for iron bioreduction. Based on sorting the outcomes in related fields at home and abroad, the impacts of different electron shuttles (humic substances, quinones, sulfur species, cell-secreted compounds and solid carbon materials, etc.) on microbial reduction of iron oxides and their respective mechanisms are reviewed systematically in this paper. And key issues regarding electron shuttles in environmental geology to be solved are~suggested.