Abstract: Clostridium spp.belongs to firmicutes,which is a large class of normal facultative anaerobic bacteria in intestine and can produce spores.Dozens of Clostridium strains have been reported in previous studies.Some of them were used to prevent,diagnose and treat relative human diseases,and others were demonstrated to be related to diseases including antibioticassociated diarrhea,pseudomenbraneouscolitis and so on.Clostridium mainly derives from the intestinal tract and fecal matter and consists of two types:harmful and beneficial.This paper summarizes the Clostridiurn strains that have been found in former studies,the pathogenic mechanisms of harmful Clostridium and the therapeutic mechanisms of drugs for them,and the application of products and gene of beneficial Clostridium,with an aim to provide some clues to the prevention and treatment of diseases related to intestinal Clostridium.