Abstract: Short chain fatty acids such as acetic acid, propionic acid, butyric acid in human body are mainly produced by anaerobic glycolysis colon from un-digested carbohydrates. Short chain fatty acids in the colonic lumen can not only be used as the main energy source of the intestinal mucosal cells, but also reduce the generation of pro-inflammatory cytokines and colitis. What's more, the short chain fatty acids can play a role in inhibiting tumor cell proliferation, inducing tumor cell differentiation and apoptosis, as well as decreasing carcinogenesis probability. This paper introduced the producing mechanism of short chain fatty acids.The metabolism and physiology functions of short chain fatty acids were also summarized.