Basic research on pediatric diseases is critical for clinical translation. Due to their physiological characteristics, rats are often the preferred choice for constructing disease models in this field. The dynamic nature of child growth and development, along with differences in organ maturity and immune responses compared to adulthood, necessitates the consideration of age matching in rat models to reduce experimental errors. However, there is currently a lack of reliable evidence for determining equivalent ages between species. Moreover, existing literature provides only limited in-depth attention to this issue. Therefore, this paper systematically reviews the correspondences between rats and humans across multiple dimensions of the life cycle, summarizes and analyzes available age conversion models, and aims to provide a scientific basis for selecting the age of experimental rats in pediatric disease modeling.