This study presents deep insights into the microbial adhesion and community dynamics of adhered and planktonic microorganisms during the anaerobic digestion (AD) of leaf, epidermis, and pith of corn stalk (CS). Microbial adhesion regularity varied with the part of CS. Overall, hydrolytic bacteria (Ruminofilibacter xylanolyticum, uncultured Bacteroidetes bacteria RII-AN097, uncultured Prolixibacteriaceae bacteria, Proteiniphilum sp. S20) and fermentative bacteria (Enterobacter hormaechei, Mobilitalia sibirica, Sphaerochaeta associate, Marinatabiaceae bacteria Ai-910, uncultured Planctomycetes bacteria, Kosakonia cowanii) would adhere to the surface of feedstock to synergistically degrade CS according to the full-length 16S rDNA gene sequencing. Acidification (uncultured Sedimentibacteriaceae sp.) and methanogenesis microorganisms (Methanosarcina barkeri str. Fusaro, Methanosateta spp.) mainly played a role in the planktonic phase for acetic acid and methane production. This study enriches the understanding of the adhered and planktonic microbial community involved in the AD, and provides a novel perspective to scientifically regulate microorganisms improving methanogenesis efficiency.