Arthroscopic ACL reconstruction has become the gold standard for ACL injury repair, and its final functional recovery is very important in addition to the exquisite surgical operation and postoperative rehabilitation care. Pre-operative care: ① Psychological care: ACL reconstruction is a new surgical technique, and many patients do not understand it and have suspicion, fear and nervousness. According to the personality characteristics of patients, we use kind attitude and easy-to-understand language to make patients understand the purpose, steps, safety and possible problems during and after surgery, and how to cooperate as a patient. ②General preparation: do all the preoperative preparations according to the routine, do all the auxiliary examinations, and do the skin preparation 1d before surgery. ③Preoperative rehabilitation exercise and education: preoperative patients should be instructed and taught to perform quadriceps and cord muscle strength exercise and affected knee mobility exercise. If the preoperative muscle strength is poor or the exercise method is not mastered, the postoperative exercise will be afraid to practice due to pain, which will cause more serious muscle atrophy of the affected limb and make recovery difficult, and at the same time is not conducive to the elimination of limb swelling. Therefore, we must repeatedly and patiently explain the importance of exercising the quadriceps muscle to patients and teach them the exercise method, so as to lay a good foundation for the successful completion of the rehabilitation program after surgery. Postoperative care: ①General care: closely observe the changes in vital signs and blood seepage from the incision dressing after surgery, apply pressure bandages to the knee after surgery, routinely place a soft pillow behind the knee, and elevate the lower limb by 15-20° to facilitate venous return and reduce swelling. ②Special care: brace application. To prevent postoperative knee extension limitation and control abnormal lateral stress, a special brace needs to be worn for 12 weeks after surgery. Ice packs on the affected area subject the local blood vessels to mechanical stimulation and cold stimulation to induce vasoconstriction, reduce joint bleeding and exudation, and at the same time reduce pain. Postoperative rehabilitation and discharge guidance ① Early rehabilitation exercise: instruct patients to exercise from 0 to 2 weeks after surgery: ankle pump exercises, quadriceps and cord muscle stretching exercises to prevent lower limb venous thrombosis and prevent muscle atrophy. Mobility exercises, closed chain flexion activities of the affected knee should be started in the 1st postoperative day, gradually, reaching 90° in 2 weeks. The exercise of hip adduction, abduction, forward flexion and back extension was carried out to maintain the strength and coordination of the hip muscles. ②Late rehabilitation and discharge guidance: 4 weeks after surgery, 120° knee flexion, 70% weight-bearing. 8 weeks to reach full range of motion, abandon crutches and walk, emphasize normal gait. 12 weeks to jog, lateral movement training. 16 weeks to jog long distance when muscle strength is satisfactory. 5 to 6 months to carry out flexibility and skill training, and start normal sports activities after satisfaction. At this stage, nurses need to frequently ask and supervise patients to exercise and mobilize family members to support them. Particular emphasis is placed on the patient’s normal gait, and the degree of not feeling fatigue and obvious pain during functional exercise. According to the condition of each discharged patient to develop an individualized rehabilitation plan and give guidance, requiring according to the plan, purposeful rehabilitation training until functional recovery. Care and rehabilitation points to note: ① Strengthening muscle exercise to prevent muscle atrophy is the key to protect the function of the knee joint. Both the patient and the provider should realize that no amount of emphasis can be placed on quadriceps exercise. The restoration of mobility is of great importance to the function of the knee. An ankylosed knee is clearly a case of failed reconstructive surgery. Preoperative exercises should be directed to achieve full mobility to facilitate the acquisition of postoperative mobility and patient mastery. ③The use of a flexion-extension adjustable brace for 12 weeks is effective in limiting functional exercise, ensuring both the function of the joint and the healing of the ligaments. ④Walking gait exercise is one of the important elements of postoperative exercise. Patients often unconsciously develop a compensatory abnormal walking gait, and correcting this gait requires the doctors and nurses to constantly communicate with the patients and point out the incorrect posture in a timely manner. The improved knee scores of our patients after surgery were inextricably linked to the use of postoperative braces and gait exercises. ⑤ Closed-chain activities have been emphasized in the rehabilitation process in recent years, as they can obtain smaller anterior-posterior laxity compared with open-chain activities and are beneficial to the recovery of proprioception. (6) Bilateral exercises are more beneficial to strengthen the quadriceps on both sides of the limb, and there is a reciprocal effect that can increase the strength of the injured limb by as much as 30%, so bilateral exercises should be performed. (7) The whole rehabilitation exercise process follows the principle of gradual and individualized treatment, and the amount of exercise is increased or decreased according to the response after exercise and the next day. Clinical practice shows that short and multiple exercises per day are more effective than long exercises on alternate days.