The first thing to look at is whether it is a permanent tooth or a milk tooth. Milk teeth usually do not need to be treated, while permanent teeth are usually treated with resin restoration, apical induction molding, implantation, etc. If it is a milk tooth, it can be left untreated if there is no damage to the permanent tooth embryo and it does not affect eating. 1. If it is a milk tooth, there is no damage to the permanent tooth embryo, and if it does not affect eating, you can leave it untreated and wait for the milk tooth to fall off and grow a new permanent tooth. If the looseness is large, you can extract the milk teeth and observe the eruption of permanent teeth, and if it is difficult to erupt, you can do eruption assisting surgery, and if the eruption time of permanent teeth is still long, you need to maintain the gap. 2. If it is a permanent tooth, you need to go to the hospital to do dental repair according to the situation. If the nerve is not exposed and there are broken pieces retained, dental bonding can be done or composite resin material can be used to repair the defect. If the tooth has exposed the nerve, you need to do root canal treatment or apical induction molding, depending on the development of the root tip. 3. If the damage is severe enough to make it difficult to retain the affected tooth, it needs to be extracted and then restored with an implant in adulthood, and the gap needs to be well maintained in the meantime. An 8-year-old child with a knocked-out tooth should seek prompt medical attention and take the best treatment plan to avoid delay.