Drawing fluid is not very harmful to the knee. Knee effusion may be due to irritation from synovitis, gouty arthritis and other diseases. Drawing fluid from the knee will be more conducive to recovery from the disease, and the benefits outweigh the disadvantages. When the knee joint is acutely injured, there will be accumulation of blood and fluid, etc. Bacteria can easily build up, causing infections and compression of nerves to produce pain. Drawing fluid from the knee can reduce the pressure of accumulated blood and fluid on the joint cavity, reduce swelling and help the disease recover. When the knee joint is irritated by strain and diseases such as rheumatism and gout, the accumulation of fluid is high and tends to aggravate the swelling and pain, thus affecting the activities. If the fluid is properly extracted under aseptic operation, it helps to reduce the pressure in the joint cavity, reduce the irritation of inflammation, and has a certain therapeutic effect. Fluid should be aspirated under aseptic operation in regular hospitals, and the indications for aspirating fluid should be strictly enforced. When knee effusion occurs, it is recommended to consult a doctor in time, follow the doctor’s instructions for further examination, and choose a reasonable treatment plan under the doctor’s comprehensive analysis.