This project is one of the Hosting Venues for Shandong National Games,China,2018.The site area is 65.9 hectares,located in Pingdu，Qingdao city. The Olympic Game Center is consisted of a 15000-seat stadium,a 7000-seat basketball GYM and a 1000-seat swimming pool. Public facilities such as central plaza, civil air defense works and bus station should be set up. The design concept is combined with "space efficence" theory. Firstly, through the analysis/combination and comparison of the functional elements within the buildings, this develops a mixed-functional system with flexibility and efficiency. At the same time, this step also leads to the effective reduction of building area, and derived the concept of "building bigness in small size". Secondly, through the combination with the requirements after the Olympic Games, the professionalism and versatility are considered comprehensively, which enlarges the extension of the use of sports buildings and lays a foundation for daily use of sports buildings. Finally, through circumstance analysis around the site, it excavates the urbanity and naturalness of the building.Based on all these analysis, the architectural spatial system is derived. At the overall level, this group of buildings are governed by three axes. The first one is the North-South axis, which connects the buildings,central square and urban space to form the integration of the site and city.The second one is the East-West axis, which connects the city with the river to form the exchange and interaction between nature and city.The third one is an oblique axis, which links with living areas in the northern and forms a close combination with daily activities of the surrounding residents. These three axes promote the connection between buildings and city. Besides these, different types of playground for outdoor activities are arranged to form the extension of the building and to initiate the integration with the surrounding environment.