Drooling in children’s sleep may be related to improper sleeping position, oral inflammatory diseases, dental malformation and other reasons. 1. Improper sleep position: children usually sleep in an improper position, especially in the side-lying sleep position, easy to appear drooling. 2. Inflammatory diseases of the oral cavity: children with gingivitis, periodontitis and other inflammatory diseases of the oral cavity, local inflammatory stimuli can lead to increased secretion of saliva, it is also easy to sleep drooling. 3. Malformations of dental development: children’s teeth develop malformations, especially the occurrence of convex deformities. Children’s teeth protrude forward more obviously, resulting in sleep lip can not cover the front teeth face up and down the lip, also easy to lead to sleep drooling. Parents are advised to take their children to the hospital’s stomatology department as soon as possible, and cooperate with the doctor to improve the relevant examination to clarify the cause.