Congenital cleft lip and/or palate (CL/P) is a common malformation of maxillofacial development. At present, it is believed that the etiology of congenital cleft lip and palate mainly results from genetic factors and environmental factors. Epigenetic changes induced by environmental factors may be the key factor in the occurrence of fetal congenital malformations. As one of the important epigenetic modifications, DNA methylation has been widely and deeply studied in many fields, but as a link between the individual and the environment, its application in CL/P is limited. Existing studies have shown that DNA methylation is closely related to the occurrence of cleft lip and palate. Stimulation of folate deficiency, smoking, pollutant exposure and other environmental factors can induce changes in the state of DNA methylation, thus affecting gene expression in the development of lip and palate and leading to the occurrence of deformities.