The work aims to explore the application strategy of modularization theory in the design of public facilities for large-scale sports events, and to provide new ideas for the integration of sustainable concepts in their specific design. Starting from the positive benefits of public facilities to large-scale sports events, the current situation of public facilities for large-scale sports events was sorted out and the existing problems were summarized. At the same time, the definition, characteristics and advantages of modular design were analyzed in order to explore how it could be used to solve the above problems. Based on this, five design elements and three design principles required to be focused on during design were summarized. Relying on the public facilities in the competition venues of the Beijing Winter Olympic Games, specific practice was carried out and the relationships among competition venues, sports, interactive technologies and public facilities were sorted out, and thus specific design solutions were generated. The solutions can be placed in the urban space before and after the games to promote the concept of the Winter Olympics and commemorate the Winter Olympics, and finally form a recyclable system of pre-game promotion-game time experience - post-game commemoration. The application of modular theory in the design of public facilities for large-scale sports events is of practical significance, which can not only effectively solve the problem of applicability of public facilities in different venues, but also make these facilities continue to be utilized in non-competition time through the mode of recycling, continue the impact of the event, and convey the concept of sustainable development.