With the rapid advancement of artificial intelligence (AI) technology, its integration into educational settings has become increasingly widespread, particularly in preschool education. AI tools, such as conversational agents, social robots, and intelligent tutoring systems, are being incorporated into learning activities and daily routines, thereby enhancing various aspects of children’s development. While the application of AI in education (AIEd) has been extensively studied, the majority of research has focused on higher education and K-12 settings, often overlooking the specific use of AI tools in early childhood education. This study addresses this gap by conducting a systematic literature review to explore the usage patterns, functions, and developmental impacts of AI tools in preschool education. Following the PRISMA guidelines, 17 relevant studies were reviewed. The findings reveal that AI tools, characterized by their diversity and interactivity, are effectively used both at home and in school settings, significantly contributing to the enhancement of language skills, emotional development, motivation, and other personal abilities in young children. These results underscore the importance of integrating AI tools into preschool education and offer valuable insights for preschool teachers, institutional administrators, and policymakers.