Analogous to DNA methylation and histone modification, RNA modification, as another epigenetic layer, plays an important role in many diseases, especially in tumours. As the most common form of RNA modification, m6A methylation has attracted increasing research interest in recent years. m6A is catalysed by RNA methyltransferases METTL3, METTL14 and WTAP (writers), m6A is removed by the demethylases FTO and ALKBH5 (erasers) and interacts with m6A-binding proteins, such as YT521-B homology (YTH) domain-containing proteins. This article reviews recent studies on methylation modification of m6A in gastrointestinal tract cancers.