The knee is the knee joint, and muscle atrophy after anterior cruciate ligament reconstruction of the knee is considered to be more likely to be myogenic muscular atrophy. It is mostly due to the thinning of muscle fibers as well as the small size of muscle fibers caused by wasting muscle atrophy, which leads to the patient’s local muscle atrophy and loss of muscle strength. First, the reason 1, braking: after completing the knee anterior cruciate ligament reconstruction surgery, patients often need to stay in bed for a period of time, the local limbs need to keep braking. Part of the patients due to the limbs in a long time in the state of braking, the lack of functional exercise of local muscles, easy to appear in the situation of wasting muscle atrophy; 2, surgical injury: the surgical process will inevitably cause some impact on the local blood vessels, nerves, thus affecting the local blood flow, as well as leading to the reduction of local neuron release of acetylcholine, which makes the local neurotrophic effect of the weakening, and is therefore prone to lead to muscle atrophy. This will lead to the occurrence of muscle atrophy. Rehabilitation exercise: It is recommended to let the rehabilitator make individualized rehabilitation exercise plan according to the severity of muscle atrophy. Without affecting the limb recovery, targeted muscle strength training, and gradually improve the muscle atrophy; 2, nutritional support: patients should strengthen the nutritional support therapy, in addition to ensuring the daily basic energy consumption, but also appropriate supplementation of protein-rich foods, such as meat, eggs, milk, etc., to strengthen nutritional support. Nutritional neurological drugs can also be used to assist the treatment, such as multivitamins, coenzyme Q and so on. Most of the patients can get effective improvement of muscle atrophy through active and standardized functional rehabilitation training, strengthening nutritional support and auxiliary drug treatment.