Tooth decay, i.e. dental caries, is a chronic progressive disease damage of hard tissue of teeth caused by oral bacteria and other reasons, mostly occurs in the neck and adjacent surface of teeth, and then progresses to pulpitis, periapical inflammation or periodontal inflammation, etc., such as for children may affect the normal growth and development of pediatric permanent tooth embryo. First of all, tooth decay pain may be the manifestation of stimulation or inflammation, after tooth decay develops to the superficial layer of dentin, the cavity formation is visible during the examination, generally there is no conscious symptom, but sometimes it is more sensitive to cold, heat, acid and sweet, and the symptom will disappear when the stimulation is removed. When tooth decay pain occurs, the treatment of early decay can be carried out by minimally invasive decay removal and infiltration resin, which can preserve the healthy tooth structure to the greatest extent. Most of the cavities are treated under the condition of obvious discoloration or formation of cavity, which is often called “filling”, mainly removing the decayed material eroded by bacteria and filling the cavity with resin material, if necessary with the use of sulcus closure and fluoride. Therefore, when tooth decay pain occurs, we should pay attention to find the cause and intervene in time. We should also increase the knowledge of oral health care, develop good and healthy oral hygiene habits such as timely brushing and scaling treatment, and actively seek drug or surgical treatment if the pain is more serious.