The high mobility in urban areas is one of the reasons for a large number of flyover construction. The construction of the flyover leaves space at the bottom. This space is then used by the community as a public space. The utilization of under space Tanjung Emas Semarang Flyover has led to the phenomenon of privatization. This research was conducted to identify space utilization activities and the privatization process carried out by the community. Data collection was carried out by observation, mapping, descriptive analysis. The results of the analysis show that the use of space carried out by the community is for economic activity. Meanwhile, the privatization process is carried out by making nonpermanent buildings or leaving the carts at a certain location. The privatization of space carried out by the community gives a new meaning to space which initially did not have a function in urban spatial planning, but indirectly also legitimized power over space. Spatial use activities by the community as well as community action in opting for under space the Tanjung Emas flyover can be a consideration for better spatial layout under the Tanjung Emas flyover in the future.