DNA methylation is an important epigenetic system. It plays many crucial roles in the gene regulation. With the development of the high-throughput detection techniques, the bioinformatics study has been an active hot topic in the research of DNA methylation. The major achievements and progress on the prediction of DNA methylation status, the mechanism that the majority of CpG islands are resistant to DNA methylation, the relationship between DNA methylation and other epigenetics, as well as the association between aberrant DNA methylation and the tumorigenesis were reviewed in this article.