Children with hypothyroidism may experience weight gain if not treated promptly and effectively, and prompt medical attention is recommended. Due to low metabolism, children with hypothyroidism may have low metabolic symptoms, including weight gain, easy fatigue, fear of cold, low sweat, slow speech, slow action, low tone, etc. Therefore, children with hypothyroidism may mostly put on weight. Their body temperature may be lower than normal due to decreased thermogenesis and poor blood circulation. In addition to the low metabolic syndrome mentioned above, hypothyroidism may also cause psychoneurological symptoms such as loss of concentration, memory loss, drowsiness, slow reaction, as well as symptoms such as edema, loss of appetite, abdominal distension, constipation, anemia, and growth retardation. Children with hypothyroidism should consult a doctor in time and follow the doctor’s instructions for appropriate treatment, and generally have a good prognosis and can return to normal life.