In modern society, people's lives are constantly accelerating and digitalisation is deepening its influence, transforming the world into a 'digital planet'. Coastal public spaces are an important part of urban environments characterised by a high degree of spatial permeability. They serve as open urban areas that blend ecological systems with man-made elements. However, coastal space development is often neglected. Furthermore, interaction design, while capable of meeting public needs, is not taken seriously in space design. Therefore, in order to design spaces that fulfil the needs of the users, the study focuses on the design of coastal urban public spaces and presents a design philosophy for interaction design in coastal areas. It refered to relevant interdisciplinary theories and national and international research findings as the basis for this research, and undertook a comprehensive range of activities such as detailed analysis, organisation and research. The study analyzed the issues that need to be addressed in research on the design of urban coastal public spaces, with the aim of establishing a verifiable and rational set of design methods and strategies for future guidance in practice. The aim is to understand the principles of applying interaction design to coastal public spaces and present application strategies for interaction design in coastal public spaces. Based on the understanding of the concepts of interaction design and coastal space, the author grasped the relevant research trends, and then based on the research space. Building on the methods and principles proposed, it presents several feasible strategies from the perspectives of people, environment and facilities. These strategies include the 'Functional Clarity Strategy', the 'Universal Facility Strategy', the 'Ecological Priority Strategy' and the 'Environmental Experience Strategy', which will guide and support future interaction design efforts in coastal public spaces.