Children with tooth decay pain should have a filling, or dental treatment. Children’s tooth pain needs to be treated as early as possible. Some people think that milk teeth are able to be replaced and can be left untreated, which is a wrong view. Untreated baby teeth will not only affect the normal chewing function, but also the pronunciation and jawbone development. If the decay is close to the tooth nerve, the external cold, hot, sour and sweet stimulation will be transmitted to the pulp tissue through the dentin tubules, causing the painful reaction of the tooth nerve, in this case, the infected material should be removed as soon as possible, and then the tooth should be filled to isolate the external stimulation to the pulp tissue. Painful tooth decay in children may also be caused by tooth decay reaching the dental nerve, pulpitis or apical inflammation can cause tooth pain, which requires root canal treatment to remove the infected nerve, followed by root canal disinfection and finally a tight root canal filling to prevent reinfection. If left untreated, the inflammation can further infect the chewing muscles causing interstitial infection. Therefore, children with tooth decay pain need to have the infected material removed and either a direct filling or root canal treatment.