Abstract: 【Objective】 The combined use of Digital Elevation Model (DEM) and Discrete Fracture Network (DFN) enables seepage simulation of complex fractured rock masses at the regional scale, but existing methods still face significant challenges in computational mesh generation and regional-scale fracture-bedrock coupling modeling. 【Methods】Based on the Equivalent Matrix–Discrete Fracture Network (EMFN) model, a high-precision modeling method suitable for seepage analysis of fractured rock masses at the regional scale is proposed by introducing the Computational Geometry Algorithms Library (CGAL) and Constrained Delaunay Triangulation (CDT) technology. The DEM elevation data extraction process is optimized to conduct dense sampling in key areas for preserving topographic details; combined with 3D surface mesh reconstruction and fracture network generation based on geostatistical laws, a complete technical chain from original DEM data to numerical seepage calculation is realized. 【Results】The constructed computational mesh is characterized by uniform size and high topological quality. The effectiveness of the proposed model is verified by comparing its results with those of COMSOL in a typical crossed-fracture case, and the model is further applied to a seepage engineering case of a coastal mountain fractured rock mass. The modeling results show that the proposed DEM–DFN coupled model can effectively characterize the seepage field characteristics at the mountain scale: groundwater converges and discharges toward low-altitude and coastal low-lying areas along the terrain slope, and the overall hydrodynamic pattern is consistent with the regional hydrological cycle laws. 【Conclusion】The DEM mesh conversion and model adaptation technologies proposed in this paper effectively improve the modeling limitations of traditional methods under complex terrain conditions, and significantly enhance the simulation accuracy and engineering applicability of fractured rock mass seepage.