The invention discloses a smart children tooth-brushing guiding system. The system comprises smart training toothbrush hardware, an application software system installed on a mobile smart terminal, and cloud service, wherein the smart training toothbrush hardware comprises a toothbrush body, a motion sensor module, a processor module, a wireless communication module and a power supply module which are arranged on the toothbrush body; the application software system is installed on the mobile smart terminal, has functions of receipt receiving and transmitting, tooth-brushing posture detection and evaluation, tooth-brushing action guiding, smart reinforcing, data uploading to cloud and the like; the cloud service is deployed on Internet public cloud, and is used for providing history record storage, data analysis, ranking sharing and the like. According to the smart children tooth-brushing guiding system, children are guided to form a correct tooth-brushing posture and an excellent tooth-brushing habit by a game interacting mode, tooth-brushing entertainment and motivation of children are improved, and a smart living mode for future home is provided.