1, the development of children's brain structure and function has a roughly stable order and stage; There is a certain order of human knowledge and experience, and children must follow this order when mastering human knowledge and experience. From mastering knowledge to changing psychological function, children have to go through a process of constant quantitative and qualitative change. Therefore, the age characteristics of children are stable.

2. Children develop under certain social and educational conditions, so with the development of the times, the age characteristics of children's psychological development have also changed to some extent. The age characteristics of children's psychological development vary with different educational conditions.

3. Children's age characteristics are stable, so we can use the previous research results to understand and educate contemporary children. Children's age characteristics are changeable, so we should create good social and educational conditions for children and promote their development.

Characteristics of children at different ages:

1, fetal period. From the formation of fertilized eggs to the birth of the fetus, about 40 weeks is the fetal period. During this period, the fetus mainly develops muscles and accumulates fat, and its weight increases rapidly. But at this time, the fetus depends entirely on the mother for survival, and the mother's nutrition, health and feelings have a great influence on the growth of the fetus. Therefore, health care during pregnancy and fetal health care are very important.

2. Neonatal period. The 28 days after the birth of the fetus is the neonatal period. Neonatal period is a stage in which children's physiological functions are adjusted and gradually adapt to the external environment. However, due to the imperfect physiological adjustment and adaptability of newborns, not only the incidence rate is high, but also the mortality rate is high, which should be paid attention to.

3, infancy. From birth to 1 year-old is infancy. This period is a period when children grow and develop very vigorously after birth. Although there is a great demand for nutrition and energy, due to the imperfect development of digestive system, it is easy to lead to malnutrition, so breastfeeding is recommended. The baby's immune function is still not perfect, so we should pay attention to receiving vaccination in a planned way.