Abstract: DNA methylation is one of the most common types of epigenetic modification, among which 5-methyl-cytosine（5 mC）, the most common methylated modification in mammalian genome, is involved in many important life activities. Abnormal alterations in the content of 5 mC are closely related to the occurrence and deve-lopment of diseases, especially cancer. Although the most common method used to detect 5 mC methylation is based on bisulfite-converted next-generation sequencing, there are still some drawbacks, including degradation of DNA molecules, complicated processing, short-reading length, low specificity and so on. In recent years, nanopore sequencing has been developed in the detection of DNA modification due to its ability to directly detect DNA modifications and the advantages of long-reading length, high throughput and speed. This review will briefly introduce the formation of 5 mC modification in DNA and its classical detection methods, and mainly focus on the application of nanopore sequencing technology in the detection of DNA 5 mC modification.