Caring for children is caring for tomorrow. To improve the quality of the nation, the healthy growth of children’s body and mind is the key. Cognitive science is a highly regarded research field in the world today, and the search for quantitative indicators of children’s cognitive science is a common problem for scholars at home and abroad. The cultivation of children’s cognitive ability is directly related to whether children can become useful talents in the future society. Therefore, how to truly understand the psychological characteristics of children at different ages and to seek scientific quantitative indicators is an urgent problem in medicine, psychology and education at present. The environment and education play a decisive role in cognitive development. Currently, schools and families focus more on the education of students’ knowledge and skills, while paying relatively little attention to the core content of children’s learning and education – cognition. It is often said that children should “win at the starting line”. Under the influence of various “genius” stories, many parents let their babies receive knowledge education in advance, trying to get the effect of “early education, early success”, is this really scientific? The research results of the Brain Science Research Center of Changzhou First People’s Hospital give a relatively objective explanation. Cognition is human’s understanding of the objective world and guides human’s social practice activities. The reason for the differences in children’s cognitive development is closely related to children’s brain development and the different psychological characteristics of each stage. The brain is the most structurally and functionally complex tissue in living organisms and an extremely sophisticated and well-developed information processing system that governs the higher-level human activities of language, thinking, feeling, emotion, and movement on a daily basis. It is often assumed that children’s cognitive abilities are progressive. In this study, by analyzing the brain wave responses of children at different ages when they receive different external stimuli, we found that children’s cognitive development is not uniform, and each cognitive function has its own characteristics and patterns of development, which are interrelated with each other. Among them, the critical period for the development of cognitive functions is from 9 to 10 years old during the school age. The development of children’s cognitive ability has inherent rules, and different age groups have different cognitive characteristics. The French thinker and educator Rousseau said, “Nature wants children to be like children before they become adults. If we disrupt this order, we will cause some fruits to ripen early, they will grow neither plump nor sweet, and they will soon rot. That is, we will create some young doctors and old children who are young and old.” Teaching children according to their abilities is more in line with the laws of their physical and psychological development. It is not advisable to educate children according to their characteristics and laws. In life, parents are often too concerned about their children’s fever, cough and sneeze. There is nothing wrong with this, as physical illness is indeed the number one enemy for weak children. However, it is not enough to simply focus on the child’s physical condition; a truly healthy child must be not only physically healthy, but also mentally healthy. Attention deficit hyperactivity disorder (ADHD), epilepsy, conduct disorder, oppositional defiance, and many other disorders can cause cognitive dysfunction in children, which causes great distress to educators and families alike and is a common concern in the current society. Therefore, we believe that a meticulous and systematic exploration of the cognitive abilities of normal children and children with cognitive disorders under different tasks is essential and also a cutting-edge research topic. According to a year of consultations at the Child and Adolescent Counseling Clinic of Changzhou First People’s Hospital, half of the children attending the clinic have ADHD problems. There is no uniform method of treatment, but each child’s characteristics must be individualized and comprehensive treatment plan, using biofeedback and psychotherapy combined with sand tray therapy equipment and other joint treatment methods, so that the child gradually recovered, physical and mental growth can be healthy. Some young parents either do not understand the significance of the natural flow of emotions to their children’s mental health, or lack the corresponding patience, they often do not allow their children to express their emotions openly and freely, especially when the child appears to have bad emotions, they force the child to repress themselves, and some parents even use corporal punishment or disguised corporal punishment to repress the natural flow of emotions of their children. Parents should realize that keeping their children psychologically healthy is necessary for their children’s healthy growth and is a responsibility that every parent should take. Only if everyone pays high attention to children’s mental health can each child have a brighter tomorrow.