In the past three decades, the research goal of service design has gradually shifted from demonstrating its significance and analyzing related design practices, to further exploring the theoretical framework, methods and tools. Touchpoint is one of the core research areas of service design. The in-depth understanding and application of touchpoints play an important part in establishing a reliable foundation of research and practice in this field. This paper summarizes the origin, definition, classification, significance, research status and trend of service touchpoint through a comprehensive survey of relevant academic research at home and abroad. It is aimed at helping design researchers to better understand, observe and design complex services.Touchpoint is the contact point between the service provider and the user, which has multiple attributes such as tangibility, interactivity, time and experience. The integrated experience of a series of touchpoints constitutes the overall user experience. At the same time, touchpoints are the central material and the main design component of service modeling and innovation. The study of the basic theory of touchpoints and the development of related tools are important research directions in service design.