In the distal femur and proximal tibia, and the lower surface of the patella is covered with a layer of smooth tissue called articular cartilage, in order to make them smooth and free movement, in the femoral condyles and tibial plateau there are two cartilage pads (meniscus) is located in between the two bones, that is, the lateral meniscus and the medial meniscus, which is like a “cushion” to protect the two articular surfaces, absorb downward shock, especially when excessive flexion and extension, this role is more obvious. They act as “cushions” to protect the joint surfaces of both and absorb downwardly transmitted shock, especially during hyperflexion and hyperextension. When jumping from a height, the knee is subjected to considerable force from gravity, but the cartilage of the femur and the platysma is not damaged because of the presence of the meniscus. Simply put, the meniscus has three important functions: 1) stabilizing the knee joint. 2) transferring the load of the knee joint. 3) promoting intra-articular nutrition. It is because the meniscus plays the role of load stabilization, to ensure that the knee joint for years of weight-bearing exercise without injury. However, due to long-term wear and tear and extrusion, degenerative changes in the elderly, this cumulative damage beyond the meniscus tolerance, resulting in meniscus injury. Clinical manifestations are: localized pain in the knee joint, tenderness, swelling, inability to fully straighten the knee joint, the knee joint rattles during activities, the knee joint hits the soft leg, the pain is aggravated when going up and down the stairs, the patient is conscious of the tearing sensation and crunching sound in the joint, when checking the patient, make the patient to straighten the 130. 140. can be accompanied by interlocking symptoms of the joint injury, and the Mai’s sign is positive. Imaging studies can help to confirm the diagnosis. In particular, CT and MRI have a higher diagnostic rate. Meniscus injury is extremely difficult to heal because of its poor blood supply, most of it is avascular, only 25-30% of the lateral side near the joint capsule has blood supply, so it is difficult to repair. At present, conservative treatment is generally used first. Manipulation therapy can relieve the symptoms of knee interlock by rotating the calf internally and externally to make the calf flexed and then straightened as much as possible, or immobilization therapy by braking, fluid pumping, bandaging with elastic bandage, etc. If conservative treatment is ineffective, arthroscopy can be used. Arthroscopic surgery is feasible for those who are ineffective in conservative treatment, and microscopic revision, partial excision, and suture are very beneficial to the knee joint, avoiding premature hyperplastic degeneration of the knee joint caused by total excision of the meniscus injury. Therefore, the introduction of arthroscopic technology is a great blessing to patients with meniscus injury.