To learn preschool hygiene well, we must first understand the main significance of this subject, that is, to study, protect, promote and develop the health of preschool children. We can study the factors affecting children's health from the anatomical and physiological characteristics and growth and development laws related to their age. To study measures to promote children's health; To study the methods of evaluating children's health. The main research methods include investigation and statistics, experiment, physical examination, observation, action research and case analysis.