A new tree-based grid environment (called TGrid) is presented in this paper after analyzing the problems in current grid environments. TGrid supports high performance computing, subject-oriented resources sharing and the next generation requirement modeling and it also achieves bottom-up, multi-level and demand-oriented abstraction and fusion of multiple resources. And it organizes grid nodes and integrates multiple resources in the tree structure that conforms to the natural hierarchical organization structures, easily achieves hierarchical management, also may reduce load on the central node (server) and realize load balancing for large-scale applications, improve the efficiency of resource searching. After introducing the Conceptual Model and the Resource Abstract Model for TGrid, the key problems of TGrid implementation are discussed and analyzed. Finally, it focuses on the task allocation algorithm using dynamic load balancing for large-scale applications in TGrid and the experiment results show the effectiveness of this algorithm. TGrid provides a new solution for Grid application demands.