Osteoarthritis of the knee (OA) is a chronic progressive osteoarthritis that endangers the health of middle-aged and elderly people, causing chronic pain and difficulty in walking, which seriously affects the quality of people’s daily life. The cause of the disease is unknown and may be related to multiple factors such as aging, obesity, genetics, trauma and decreasing estrogen levels. The essence of osteoarthritis is cartilage damage, articular cartilage defects, and the disease continues to develop, involving the entire joint, resulting in inflammation of the joint capsule and synovial membrane and muscle atrophy around the joint. It is a worldwide problem. Due to the increased life expectancy of the population, 50% of people over 60 years of age have osteoarthritis on X-ray. Of these, 35% to 50% have clinical manifestations, and 80% of those over 75% have osteoarthritis symptoms. The basic principle of osteoarthritis treatment is, first of all, to relieve pain, to improve joint function, and at the same time to slow down the progress of the disease, that is to say, to protect the joint cartilage, to slow down the process of cartilage destruction, and ultimately to improve the quality of life of patients. Such as choosing the appropriate occupation that is conducive to disease recovery, using physical therapy, weight control, exercise, application of auxiliary support. Commonly used medication means: giving symptom relieving drugs such as acetaminophen, non-steroidal anti-inflammatory analgesics, etc., and local injection of steroid hormone, sodium vitaminate, etc. in joints with more serious symptoms. These traditional conservative treatments can basically relieve the symptoms, improve joint function, and improve the quality of life to a certain extent. However, the treatment time is long and easy to relapse. The use of hormones somehow aggravates the destruction of cartilage and accelerates the disease process instead of slowing it down. The more severe symptoms require arthroscopic joint cleaning up to knee arthroplasty, which is often a concern for patients because of the high cost of surgery. In recent years, ozone therapy, a new minimally invasive technique, has been used in the treatment of osteoarthritis of the knee with satisfactory results. Ozone (O3) is a strong oxidant consisting of three oxygen atoms, with a half-life of about 20 min at room temperature, easily decomposed and soluble in water, and can only be produced on site for immediate application. It is a light blue gas with a special odor, and compared with O2, O3 has a high specific gravity, and the effect is completed in an instant without permanent residue. The principle of medical ozone treatment for joint diseases is that when ozone is injected into the joint cavity, it immediately reacts with biochemical molecules (such as proteins) in the synovial fluid to produce ROS, LOPs (lipid oxidation productions), causing (1) inactivation or inhibition of protein hydrolases and inflammatory cytokines to reduce inflammation. (2) Inducing the production of antioxidant enzymes: superoxide dismutase, glutathione superoxide dismutase. Increase synthesis of mesenchymal cells and articular cartilage. Stimulate the proliferation of cartilage and fibrogenic cells and play a role in repair. (3) Inhibit the release of bradykinin and inhibit the synthesis of inflammatory mediators PGs, which can reduce pain (stimulate the release of cytokines to neutralize local inflammatory mediators, such as: IL-1, IL-12, IL-15, TNF to reduce inflammation). (4) Promote the release of immunosuppressive factors (such as TGF-β1, IL-10) and inhibit immune response. Foreign experimental studies have shown that ozone has the effect of oxidizing proteoglycans, anti-inflammatory effect, neutralizing the excess production of oxides, antagonizing the release of immune factors in inflammation; dilation of blood vessels, after injection, acts directly on nerve endings and inhibits the release of intermediate neurons and enkephalins and other substances, thus achieving analgesic effects. Ozone (O3) joint cavity injection as a new minimally invasive technology in our pain department in recent years, through the use of German ozone therapy instrument joint cavity and surrounding ligament pain injection injection, combined with local Chinese medicine external application, internal Chinese and Western medicine, appropriate rest, reduce weight bearing, proved to be safe, simple, low cost, multi-action characteristics, is a rapid and effective method for the treatment of degenerative knee osteoarthritis in the elderly.