The developmental psychology of preschool children is a science that studies the psychological changes of children from birth to preschool development. Preschool developmental psychology plays an important role in children, families, educators and society: 1. Providing care and guidance for children: Preschool developmental psychology tells us that children's age is very important for their physical and psychological development, so parents, teachers and other adults need to understand their needs and behaviors and provide them with appropriate support and guidance. 2. Guidance for educators: Preschool developmental psychology helps educators to understand children's cognitive and language abilities, including how children learn and develop important social and emotional skills, which helps them to make better educational plans and teaching strategies. 3. Help families create a healthy family environment: Preschool developmental psychology can guide parents to create a good family environment for their children, strengthen parent-child relationship through parent-child interaction and emotional communication, and cultivate children's emotional and cognitive abilities. 4. Research on children's psychological problems: Preschool developmental psychology studies children's development and their psychological problems, such as emotional problems, behavioral problems and social problems. Studying children's problems is helpful to promote children's mental health and happiness, avoid or deal with psychological problems as early as possible, and prevent serious psychological problems. In a word, the developmental psychology of preschool children is very important to the all-round development of children's physical and mental health, which helps to promote children's all-round development and promote their positive growth and healthy development.