Data grids provide researching groups with data management services such as Grid-Ftp, Reliable File Transfer Service (RFP), and Replica Location Service (RLS). Especially, Replica Location Service could improve data availability by storing multiple data to the distributed location. In this paper, we propose Tree-based Replica Location Scheme (TRLS) that could support users to decide optimally the location of multiple replicas as well as the number of replicas. In addition to, we could decide the number of replicas to satisfy user's requirements by minimizing cost.