In recent years, it has already run into a common view that "tumor is a metabolic disease", and the reprogramming of tumor metabolism has become the focus of current research. One-carbon metabolism involves folate cycle, methionine cycle and trans-sulfuration pathway. By utilizing these three ways, one carbon unit can regulate tumor growth and proliferation with the production of pyrimidine, thymidine, s-adenosine, glutathione, etc. This paper mainly describes the production and utilization of one carbon unit in tumor, as well as the interaction between one carbon metabolism and tumor development, providing new ideas for studying the mechanism of one-carbon metabolism in tumorigenesis and the treatment of nutrients in tumor.