Children’s knee joint ringing, may be a normal physiological phenomenon, may also be patella subluxation, congenital discoid meniscus, etc.. 1. Normal physiological phenomenon: due to the child’s bones are not fully developed, in the knee joint bending and stretching, may lead to abnormal sliding of the tendons around the joint, causing the joint popping, this is a normal physiological phenomenon, with the growth of the baby, this kind of ringing will gradually disappear, generally do not need to be treated. 2. Patellar subluxation: usually caused by patellar trauma. For example, children’s strenuous exercise or acute bump caused by the patella inner and outer support band imbalance, resulting in abnormal patella trajectory, resulting in patella subluxation. Often manifested as knee pain, and in the activities will have a thump thump thump sound. 3. Congenital discoid meniscus: it is a congenital deformity. In infancy, there is usually no clinical manifestations, but as the child’s age increases, the amount of activity increases, usually manifested in the affected side of the knee joint popping, when the symptoms are serious, there can be limited joint activity, pain, limp and so on. To summarize, if the child’s knee joint ringing and other uncomfortable symptoms, it is recommended to consult a doctor in a timely manner, to clarify the cause of the disease, targeted treatment.