Rattling of bones when walking may be related to physiological reasons such as joint popping, as well as pathological reasons such as joint injury, osteoarthritis and intra-articular free bodies. 1. Physiological reasons: if there is no pain or limitation of activity, it is generally physiological joint popping, which may be caused by air bubbles in the synovial fluid in the joint cavity, and the uneven pressure in the cavity due to walking causes the air bubbles to be squeezed out and give out the sound, which usually doesn’t need any special treatment. 2. Pathological causes (1) Joint injury: due to the injury of meniscus, ligament, cartilage and other parts of the joints, causing abnormal friction when walking, and the phenomenon of rattling of bones when walking. (2) Osteoarthritis: Rattling of walking bones may be caused by osteoarthritis. As osteoarthritis may lead to a large area of articular cartilage peeling off, making the subchondral bone leakage, and the joint space narrowing, friction will be formed between the bones when walking activities, which will cause the rattling sound. (3) Intra-articular free body: Joint free body is the damaged bone or cartilage that forms a wandering cartilage mass in the joint. When the free body is stuck in the joint and rubs between the joint surfaces during joint movement, it will cause a rattling sound and the phenomenon of rattling bones when walking occurs. There may also be other reasons for the rattling of walking bones, it is recommended to go to the hospital in time to improve the examination, to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.