Non-surgical treatment is mainly symptomatic and muscle strengthening. 1. After ACL tear, the joint stability is reduced due to the absence of the ligament, thus the joint stability needs to be maintained compensatively by the strength of the muscles around the knee joint. Therefore, exercising the lower extremity muscles is the key to non-surgical treatment, especially the quadriceps in the anterior thigh. 2. Other treatments include the use of anti-inflammatory and analgesic drugs to relieve pain and eliminate swelling, and the use of glucosamine drugs to nourish the articular cartilage. 3. Change the way of exercise and reduce the amount of exercise, no running, climbing, ball and other sports. Reduce activities such as climbing and prolonged walking in the occupation.