Information service in the grid provides the ability to discover and monitor resources which is fundamental for the grid infrastructure. A framework of a tree-based grid information service (TGIS) is proposed in this paper. This framework is based on GT's MDS. MDS uses centralized GIIS to index services. Performance study shows that GIIS can not sustain large users and GRIS. Our TGIS framework uses decentralized GIIS to solve that problem. We construct each GIIS node in a tree structure which can solve system performance and scalability issue.