Whether the caries of the six-year-old child needs treatment or not, it needs comprehensive judgment, depending on whether this caries is the front tooth or the back tooth, as well as the depth of decay, the child’s cooperation and so on, as follows: 1, no treatment is needed: if the front incisor is decayed, at the age of six, this incisor should be the incisor of the milk tooth, which may be about to be replaced. There is no any painful symptom, moreover, there is no inflammation of the root tip. From the point of view of endodontic treatment, this kind of baby tooth can be left untreated, because it will be replaced soon, maybe within a few months, so it can be left untreated. If from the point of view of aesthetics, it can be treated with filling. 2.Treatment is needed: If the tooth behind is decayed, even though it is six years old, it still needs to be treated with filling actively, because the last molar behind can be replaced only when it is about 12 years old, and the penultimate molar can be replaced only when it is about 10 years old. Therefore, the decay of the milk molar should be treated actively at the age of six. If the decay of papillary molar is very serious, it can not be preserved at the age of six, or even need to be extracted, and a gap retainer is needed to maintain the integrity of the teeth.