Synovitis is a disease that causes joint pain, of which synovitis of the knee is the most common type of synovitis. Synovitis of the knee is a local inflammation of the joint due to various causes, such as trauma, infection, strain, degeneration, and immune response. It is characterized by localized swelling, swelling and pain, fluid accumulation, even blood accumulation, and impaired movement of the joint. Treatment is mainly based on improving local blood circulation and promoting the absorption of inflammation and joint exudate. There are various methods of treatment such as medication, physical therapy, etc. Among them, acupuncture is used to treat synovitis. Among them, acupuncture treatment for synovitis is mainly based on local blood flow through the meridians, often using methods such as general acupuncture, electroacupuncture, fire acupuncture, warm acupuncture and cupping, in order to achieve the purpose of activating blood stasis, opening up the meridians and relieving swelling and pain. Acupuncture therapy can separate the adhesions and improve the permeability of synovial membrane, which has good effect on knee synovitis.