Abstract: Using a computational module for enhanced geothermal systems (EGS) incorporating discrete fracture networks (DFN), developed based on the IGG-hydrate algorithm interface, this study systematically analyzes the influence of key geological and engineering parameters on the long-term heat transfer performance of EGS. The results demonstrate that: (1) The degree of fracture network development governs the transition of heat transfer modes from matrix-dominated conduction-convection to preferential flow through fracture networks. However, higher fracture density is not always beneficial; excessively high density combined with small well spacing can cause early thermal breakthrough due to insufficient fluid residence time, leading to lower initial outlet temperatures compared to matrix-dominated models. This highlights the critical need to match reservoir stimulation intensity with system efficiency. (2) Fracture conductivity (permeability) is crucial for long-term sustainability. Low-permeability fractures promote sufficient initial heat exchange but have limited sweep range, resulting in rapid long-term performance decline. Although high-permeability fractures may experience earlier thermal breakthrough, their strong heat recharge and extensive sweep capacity allow sustained heat extraction from a larger reservoir volume, maintaining high temperatures and power output in the mid to late stages. (3) Injection flow rate involves a trade-off between short-term output and long-term sustainability. High flow rates enhance early power generation but accelerate thermal breakthrough and reduce system lifespan. Optimization must consider economic models, energy demand, and reservoir heat transfer characteristics to maximize lifecycle benefits. These findings indicate that efficient and sustainable EGS development requires an in-depth understanding and synergistic optimization of the complex coupling between geological conditions and engineering design.