To reveal the mechanism by which oriented alignment of thermally conductive fillers enhances the thermal conductivity of polymer matrix composites， a two-dimensional steady-state heat conduction numerical model was established for graphene/fluoropolymer composites. The effects of filler volume fraction， aspect ratio， and orientation angle on the effective thermal conductivity of the composites were systematically investigated. The results show that the effective thermal conductivity of the composite increases with the rise of graphene volume fraction and aspect ratio， but decreases with the increase of orientation angle. Graphene orientation exhibits a significant regulatory effect on directional thermal conductivity， and there is a cosine relationship between orientation angle and effective thermal conductivity， with the average coefficient of determination R² of the fitting equation exceeding 0.99. At a volume fraction of 30% and an aspect ratio of 20∶1， as the orientation angle decreases from 90° to 10°， the effective thermal conductivity of the composite increases from 0.233 W·m^-1·K^-1 to 1.285 W·m^-1·K^-1， representing an increase of approximately 450%. This study demonstrates that oriented alignment of thermally conductive fillers can optimize the geometric matching between fillers and heat flow direction， improving the continuity and directionality of internal heat conduction pathways in composites， thereby significantly enhancing thermal transport capability along the target direction. The results can provide a theoretical basis for the structural design and performance regulation of thermally anisotropic high-thermal-conductivity composites.