There are several common causes of knee sports injuries: first, the most common is synovitis of the knee joint, when the knee joint sports lead to injury, if the violence is light will damage the synovial membrane, so that the synovial membrane produces inflammation, leading to the production of joint effusion. At this time, we must minimize sports to prevent synovitis. Secondly, after the knee joint sports injury, the common cause of injury is the cartilage surface of the knee joint injury. Cartilage surface belongs to the non-renewable tissue, once damaged, it is difficult to regenerate, so it is necessary to avoid the damage of articular cartilage. In addition, knee sports injury, especially easy to cause knee meniscus damage, and once the meniscus damage will be very difficult to treat. Sports injuries can also lead to damage and rupture of the medial and lateral collateral ligaments and cruciate ligaments if the violence is particularly high. The best way to prevent these sports injuries is to avoid overdoing the knee as much as possible.