There are many ligaments in the knee and the main ligament injuries are medial collateral ligament injuries, lateral collateral ligament injuries, and cruciate ligament injuries. The question of how long it takes to recover from a ligament injury is related to the patient’s type of ligament injury, the extent of the injury, the degree of recovery, as well as the patient’s physical condition and even the type of occupation. Knee cruciate ligament injuries, for example, are categorized as anterior cruciate ligament injuries and posterior cruciate ligament injuries. Ligament injuries are usually treated with conservative and non-surgical treatments. For severe tears and ruptures of the cruciate ligaments, surgical treatment is usually required, especially for athletes or patients with high athletic demands, otherwise degenerative damage to the joint structures may be accelerated due to decreased stability of the joint. Post-operative rehabilitation usually takes at least 3-6 months or even longer before return to sports. For patients with mild ligament injury, good stability, or low requirements for sports and functions, simple partial injury of cruciate ligament can be treated conservatively, such as acute injury in the early stage can be fixed in the resting position of the affected knee in a brace, early exercise of quadriceps and ankle pump exercise, etc., according to the situation of 4-6 weeks after the disappearance of symptoms and gradually restore the mobility of the joints, most of the patients! Most patients are satisfied with the recovery of joint function after non-surgical treatment. Similarly, for patients with medial and lateral collateral ligament injuries and simple tearing of the knee joint, they should be externally immobilized in plaster or brace for 4-6 weeks in the acute stage, with regular follow-ups, and after removing the immobilization, according to the assessment of ligament recovery, they should carry out the rehabilitation activities of the knee joint gradually, and gradually restore the strength of the movement; if the ligament is ruptured and the sign of the openings is positive, they should be diagnosed in time, and should undergo surgery as early as possible, so that the recovery effect will be better. To summarize, different types of knee ligament injury, recovery time will be different, when there is pain, swelling, instability of the knee joint, etc., as soon as possible to seek medical treatment, clear diagnosis, timely treatment.