Hip synovitis in children can appear hip joint pain, localized redness and swelling of the hip joint, limited hip joint activities and other symptoms. 1. Hip pain: mainly manifested as sudden hip pain on the affected side of the child, the pain can be continued to the inner thigh and hip joint. If the child separates the affected limb outward, the pain can be alleviated. The pain worsens with movement. Pressing the joint gap, the pain is more obvious. 2. Localized redness and swelling of the hip joint: manifested as redness and swelling of the skin around the hip joint, mainly in the inner thigh, upper thigh and buttocks. 3. Impairment of hip joint motor function: the affected children may have difficulty in walking, change of walking posture, limp and other symptoms. If the above symptoms occur in children, it is recommended to go to the hospital in time for consultation and timely treatment to avoid delaying the condition.