Abstract Trap formation is the key indicator of carnivorous lifestyle transition of nematode‐trapping fungi (NTF). Here, the DNA methylation profile was explored during trap induction of Arthrobotrys oligospora , a typical NTF that captures nematodes by developing adhesive networks. Whole‐genome bisulfite sequencing identified 871 methylation sites and 1979 differentially methylated regions (DMRs). This first‐of‐its‐kind investigation unveiled the widespread presence of methylation systems in NTF, and suggested potential regulation of ribosomal RNAs through DNA methylation. Functional analysis indicated DNA methylation's involvement in complex gene regulations during trap induction, impacting multiple biological processes like response to stimulus, transporter activity, cell reproduction and molecular function regulator. These findings provide a glimpse into the important roles of DNA methylation in trap induction and offer new insights for understanding the molecular mechanisms driving carnivorous lifestyle transition of NTF.