Abstract: Cryptosporidium is a kind of enteropathogen that can infect human and other vertebrates.It was one of six major causative agents of diarrhea in human and played an important role in the prevalence of water-related gastrointestinal diseases. Further research and investigation on cryptosporidium have been carried out since 1980s~1990s because of its contamination in drinking water and the prevalence of human infection in developed countries. It has been listed as one of emerging infectious diseases by WHO and USA CDC.More attention has been paid to cryptosporidiosis as no effective drug is currently available, although most cryptosporidium infections are mild or asymptomatic. The contamination of cryptosporidium in water, the prevalence of crytosporidiosis, the risk of infection and the monitoring were reviewed and discussed in detail in this paper. The relatively restraining factors were discussed; and the major problems necessary to be concerned and solved were proposed.