Children’s pain below the knee may be caused by growing pains, ligament damage or synovitis. 1. Growing pains: As children are in a period of rapid growth and development, the pituitary gland will secrete a large amount of growth hormone to stimulate the growth of bones in the process of growth and development, which will cause rapid changes in the muscles around the joints, thus causing pain and discomfort in children’s below-knee pain symptoms, but the duration of this pain symptom is shorter and can be relieved on its own. 2. Ligament injuries: If a child exercises too much or improperly, resulting in ligament sprains, tears, etc., it will also cause the symptoms of pain below the knee of small children. 3. Synovitis: If a child suffers from synovitis due to external trauma or infection, the knee will become swollen and painful after being stimulated by the inflammation, and the child’s activities will be limited. Due to the fact that there are many factors that can cause children to have pain below the knee, when persistent pain occurs, it is recommended to go to the hospital for examination and diagnosis, as soon as possible to clarify the cause of the disease for active targeted treatment, to avoid delaying the condition that leads to aggravation of the symptoms caused by the adverse effects.