Definition: Non-formal preschool education is a form of preschool education initiated by the government, non-government or individuals, aiming at children aged 0-6 who cannot receive formal preschool education, especially vulnerable children (such as disabled children, children from poor families and ethnic minority children), relying on community resources to carry out preschool education according to local conditions. Informal education is all organized and systematic educational activities outside the formal school system, aiming at providing selective learning types for specific groups of people. (Tollsten Hu Sen, T. Nellie Postlet. International Hotels. Encyclopedia of Educational Research: Publishing House. 1990. p390-391) Compared with formal education, informal education has looser structure, more flexible time, more flexible educational methods and more direct goals, which is suitable for local conditions. Preschool education refers to the education of children from birth to primary school. There are two ways of implementation, one is family education for children, and the other is social education for children. Social education for young children refers to educational practice activities organized and implemented by society (including government, enterprises, organizations, communities and private individuals) outside the family, including school-style kindergarten education (such as nursery, kindergarten and preschool education), preschool education through mass media (such as radio, books and magazines) and community preschool education. Kindergarten education is school-style, organized by kindergartens and implemented by full-time preschool education staff according to the requirements of society, aiming at promoting the comprehensive and healthy development of children's body and mind. It has a fixed place, purpose, organization and planning, and has the characteristics of formal education. Therefore, kindergarten education can be regarded as formal preschool education, while other organized and systematic forms of social education for young children can be regarded as informal preschool education.