Abstract: In recent years, with the rapid development of microbiology, the concept of "gut-joint" axis has been put forward in modern medicine. The "gut-joint" axis plays an important role in intestinal microorganisms and joint diseases. Disturbance of intestinal microorganisms leads to chronic systemic low-grade inflammation, which further aggravates the pathological course of osteoarthritis. Regulating the balance of intestinal microorganisms may improve the symptoms of knee osteoarthritis by suppressing local immune inflammatory responses in the gastrointestinal tract or the knee. Based on the "gut-joint" axis, this paper discusses the potential effects of intestinal microorganisms on knee osteoarthritis, and the potential ways of treatment of knee osteoarthritis.