Teeth replacement in children means the loss of milk teeth and the eruption of permanent teeth in the order of first molar, mesial incisors, lateral incisors, first premolar, cuspids, second premolar, second molar, and third molar. If the upper and lower teeth have the same name, the mandibular teeth erupt earlier. Children’s tooth replacement usually occurs at the age of 5-7 years, initially the first permanent molar erupts behind the second milk molar, while the milk mesial incisors are lost, the permanent mesial incisors erupt, after which the lateral incisors erupt, and then the first premolar, cuspids, the second premolar, and the second molar erupt in order, and the third molar erupts the latest, and in some cases, does not erupt. Sometimes the second premolar erupts earlier than the cuspids. Children with abnormal timing of tooth replacement or discomfort should go to the hospital in time and receive standardized treatment under the guidance of a doctor.