Abstract: Chronic exposure to aresnic can cause many damages of tissues and organs, such as skin cancer, bladder cancer, hypertension, and diabetes.Arsenic-related health damage has been a serious public health problem worldwide.It has been reported that the occurrence of chronic arsenic poisoning and the severity of arsenic-related damages are closely related to the methylation capability of aresnic metabolism.In addition to gender, age, level of arsenic exposure and other individual factors, environmental and genetic factors have significant impact on the methylation of arsenic metabolism and the risk of arsenic poisoning.Thus, understanding of the effects of genetic and environmental factors on arsenic methylation can help to identify the key points which will be useful in reducing the risk of chronic arsenic poisoning.In this paper, we made a review on the relevant factors which affects the capability of arsenic methylation and the risk of chronic arsenic poisoning.