Knee osteoarthritis (KOA) is the highest incidence of osteoarthritis, which seriously affects the quality of life of patients. In order to update the understanding of the disease, clear diagnostic criteria and appropriate treatment were proposed. In 2018 and 2019, the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO), the Association of the Scientific Medical Societies in Germany (AWMF) and Brazil successively formulated guidelines for knee osteoarthritis, which determined different guidance suggestions through systematic evaluation of a large number of literatures and evidence-based medical evidence analysis. This paper compares and interprets the guidelines, and discusses them according to the actual situation of our country for the reference of clinicians.