Osteoarthritis of the knee mostly occurs when going up and down stairs, squatting and standing up, and the pain can be relieved after resting, but in serious cases, joint stiffness and deformity can occur. The scientific and reasonable exercise can prevent osteoarthritis of the knee to a certain extent. 1, quadriceps strength training: supine position, straighten the knee joint, tense the muscles in front of the thigh to do quadriceps static contraction. Each contraction as hard as possible and adhere to a long time, repeat several times to thigh muscles feel sore. 2, straight leg exercises: supine position, straighten the lower limbs and lift about 30 degrees from the bed, adhere to 10 seconds and then slowly put down, rest a few moments and then repeat the training, every 10-20 times for a group, training until the muscles have a sense of soreness and swelling. In addition, the appropriate amount of sandbags can be tied to the ankle for practice, and gradually increase the weight of the sandbags with the strength. 3, half squat against the wall exercise: stand against the wall, knee, hip bending not less than 90 degrees, as a half squat, adhere to 10 seconds after standing up, rest a moment and then squat, every 10-20 times for a group. 4, no weight-bearing lower limb joint active flexion and extension: supine, one side of the lower limb straight, the other side of the lower limb knee flexion and hip flexion so that the thigh as close to the chest, and then alternate exercises on the other side of the lower limb. Note: When there is obvious pain and swelling in the joint, rest should be the main focus, avoid up and down stairs, running and other exercises that put weight on the knee joint, and use crutches to reduce the burden on the joint when walking. These exercises should be done only when there is a significant improvement in joint pain and swelling, and preferably under the regular guidance of a rehabilitation physician.