[ ABSTRACT] Trillions of microbes inhabit the human intestine, forming a complex microecological community.It has been found that the gut microbiotas contribute nutrients and energy to the host, and they are also involved in the occur-rence and development of human diseases.With the continuous development of related research, there is increasing evi-dence suggesting a close relationship between gut microbiota and human diseases.The discovery of this relationship affects the development of modern health care individually.In this review, we focus on the influence factors to the diversity of gut microbiota, which has influences on colorectal cancer, aging, obesity, immunity, drug effects and malnutrition.