Since there are many causes of knee effusion, treatment should be tailored to the cause of the knee effusion. The common causes of knee effusion are chronic injury synovitis or acute synovitis. In this case, if the amount of effusion is not very large, the effusion can be slowly absorbed through traditional Chinese medicine or other physical therapy, such as herbal tonics or Chinese medicine fumigation. If the effusion is large, the pressure in the joint cavity can be relieved by extracting the effusion, or sodium hyaluronate can be injected to improve the function of the joint. For infected joint effusion, a bacterial culture plus drug sensitivity test should be done, and then the most sensitive drug should be selected according to the results of the drug sensitivity test. For joint effusion caused by tuberculosis arthritis, anti-tuberculosis treatment must be strictly administered to prevent the sequelae of joint deformity. If the joint effusion is caused by rheumatoid arthritis, anti-rheumatic treatment can be actively carried out, and hormones can be used if necessary. If the joint effusion is caused by gout, the blood uric acid should be actively reduced, and if gout stones have formed, minimally invasive surgery is required if necessary. In short, for knee joint effusion, we should first find out the cause of the disease before we can do targeted treatment.