Abstract: Finite element-based coupled analysis of tunnel surrounding rock and support serves as a fundamental underpinning for intelligent applications throughout the entire lifecycle of tunnel design, construction, and operation.. However, complex geological structures and substantial scale discrepancies between geological bodies and tunnel components pose challenges in mesh generation. Therefore, this paper proposes an adaptive mesh generation method for tunnel geological body fusion modeling based on hierarchical regional constraints. Initially, a refined integrated model of tunnel structures and the surrounding geological bodies is constructed. Subsequently, hierarchical regional partitioning is implemented based on semantic and spatial information, establishing a mesh size field to guide adaptive meshing while ensuring boundary conformity. A typical tunnel project was selected for experimental analysis, and the results indicate that the generated mesh exhibits rational density distribution, maintains consistent mesh alignment across regional boundaries, achieves an average aspect ratio of 1.7, and attains a shape factor of 0.6. The simulation analysis error is controlled below 2%.