Infectious uterine diseases are mainly caused by bacteria invasion following parturition in dairy cows. A wide range of bacteria population were revealed in the postpartum uterus of cattle, including recognized uterine pathogens such as Escherichia coli, Arcanobacterium pyogenes, Fusobacterium necrophorum; potential pathogens such as Clostridium perfringens, Klebsiella pneumoniae, Micro Streptococcus; opportunist pathogens such as Peptostreptococcus, Staphylococcus aureus. Recently, phyla of Proteobacteria, Fusobacteria, Firmicutes, Bacteroidetes, Tenericutes and a group of uncultured bacteria were observed in the uteri using molecular biology techniques. A positive correlation were found between Bacteroides, Fusobacterium and uterine diseases. G? bacteria, E. coli as representative, and G+ bacteria, A. pyogenes as representative can be detected by Toll like receptors in the endometrial cell membrane and subsequently resulted in inflammation responses, such as changes in prostaglandins type, small size of follicle and corpus luteum, reduction in serum concentration of estrogen and progesterone. Finally, this led to anestrus and anovulation, prolonged calving interval, lowing milk yield and the number of calves, which largely reduced economic profit. This review outlines the dominant microbial community in uterus after calving, correlations between bacterial species and the uterus status, recognitions of pathogen in endometrium and innate immunity, effects of uterine diseases on ovary and uterus function.