Abstract: Recently, the new bacterium genus Synergistes has been found to distribut in nature widely. However, it is uncluturable for most subseries and only covers a minor portion of the bacteria series in each habitat, with special physiological and biochemical characteristics and capability of adapting to enviroment, particularlly in the oral cavity. Being found high prevalence in periodontal, endodontic infection, it is suspected as one of the pathogens of oral diseases. This article reviewed the lastest researches on the relationship of the division Synergistes and oral diseases.