Synovitis with a large knee gap may be an intra-articular infection caused by a variety of factors such as chronic strain, acute trauma, and synovial injury to the knee joint. Generally, drug treatment, puncture treatment and surgical treatment are adopted. 1. Drug treatment: chronic strain of the knee joint, acute trauma can lead to synovial injury of the knee joint, skin tissue congestion, edema and exudate more, resulting in a large amount of fluid in the joint. Some non-steroidal anti-inflammatory analgesics such as aspirin tablets or hormonal drugs can be used to reduce the inflammation of the infection. Patients with mild symptoms can use some creams such as indomethacin cream to relieve symptoms. 2. Puncture treatment: When there is too much fluid in the knee joint, an intra-articular puncture can be used to extract the fluid to improve the symptoms. 3. Surgical treatment: when the patient after conservative treatment, the treatment effect is not good can be used to surgically remove the synovial membrane to achieve therapeutic effect. When synovitis knee gap is too large, we should go to the hospital in time to clarify the cause of the disease, and follow the doctor’s instructions to standardize the treatment.