The rehabilitation program after ACL reconstruction is more controversial and the experience and habits of different knee surgeons are constantly changing. This rehabilitation program should be interpreted and implemented by an orthopedic surgeon or a specialized orthopedic rehabilitation surgeon in communication with the patient. Because each patient’s injury and procedure is different, the individualized rehabilitation program must be developed by the surgeon or rehabilitation physician (after communication with the surgeon). 1. Post-operative wearing time of knee adjustable brace (dumpling chain type): 6-8 weeks. 2. Weight-bearing time: 2 weeks, the knee must be fully extended during weight-bearing (the brace is adjusted to 0 degree locking). 3. Joint mobility: bending up to 90° within 1 week; within 5 weeks, no more than 90°; after 5 weeks, start practicing angles after 90°. 4. Extension exercises must be started on the first day after surgery; limited extension of the knee joint is not allowed. 5. In addition to knee rehabilitation, adjacent joint activities can be started as early as possible. 6. Muscle training should be started as early as possible when pain is tolerable. 7. Patients who are able to do so, start proprioceptive training as early as possible. There will be some pain in the rehabilitation exercise. If the pain can diminish or disappear within half an hour after the exercise is stopped, there will be no damage to the tissue and the rehabilitation exercise can continue to be held. Physical strength exercises should be performed throughout the rehabilitation program. It is appropriate to perform each exercise until the muscles feel sore and fatigued, and then proceed to the next group after sufficient rest. Improved muscle strength is a key factor in restoring stability to the joint and should be maintained. The swelling of the knee joint will accompany the entire exercise process until the knee flexion and extension angles and muscle strength return to normal, then the knee swelling will gradually subside. If the swelling of the knee suddenly increases, the exercises should be adjusted, the activity should be reduced and, if necessary, medical attention should be sought. Immediately after the functional exercise, apply ice for 15-20 minutes. If the joint swelling, pain and fever are usually obvious, continue to apply ice, but do not apply ice more than 6 times a day.