Adult flatfoot is a common foot deformity, mainly manifested as medial arch collapsing, hindfoot valgus and forefoot abduction. People have a more thorough understanding of the pathological changes and pathogenesis of flatfoot with further research. There is a new expert consensus for adult flatfoot published in Foot & Ankle Inter. in 2020. The expert panel reviewed the latest literature to develop consensus recommendations for flatfoot, including its nomenclature, diagnosis, classification and operative treatment. The consensus represents a new understanding of the disease and a new concept because of the authority of its authors and the comprehensiveness of its content, and it is also a phased summary of the theoretical and clinical progress of adult flatfoot. This article gives a detailed interpretation of the content in the consensus.