Knee joint effusion needs to be treated according to the specific cause, including the following methods: 1, knee joint effusion caused by gouty arthritis, treated by lowering uric acid; 2, knee joint effusion caused by trauma, requires trauma ice treatment; 3, fracture, ligament injury, requires further MRI examination and surgical treatment; 4, knee joint effusion with unclear diagnosis needs to be punctured to extract the effusion pathology examination, according to the specific situation for the next step of treatment.