In this paper, we focus on why and how the "transgenerational twin" maps the life characteristics of cities, review the fundamental reasons of the "transgenerational twin", summarize the development process of the "transgenerational twin", and refine the classification system of the "transgenerational twin" elements and its relationship matrix, and point out the future direction of the "transgenerational twin" and its possible contributions. It summarizes the developmental process of the "transgenerational twin", refines the classification system of the elements of the "transgenerational twin" and its relationship matrix, and points out the future direction of the "transgenerational twin" and its possible contributions. We follow that urban life has three forms: physical life, social life and digital life. The material life and social life of the city evolve iteratively, so the digital life of the city must also map the material life and social life of the city to evolve iteratively. The introduction of "twinning" from the industrial production process to urban planning and construction management should address the characteristics of iterative evolution of cities, and be combined with "time", which is a core concern in urban planning and construction management. The key to "intergenerational twinning" is to see the future of the city, and to use the future to guide the decision-making of the present; the advantage of "intergenerational twinning" is to see the history of the city, and to make a scientific basis for current and future development; the scientific significance of "intergenerational twinning" is to find the future of the city in this way. The scientific significance of "intergenerational twinning" lies in the discovery of the laws of urban development. "Intergenerational Twinning helps urban disciplines to understand the interrelationships between history, present and future, as well as the connections between the multiple elements inherent in the process of urban life formation, and gives impetus to urban development.