Previous studies suggested that Mercury’s terrestrial-like magnetosphere could possess Earth-like field-aligned currents (FACs) despite having no ionosphere. However, due to the limited coverage of spacecraft observations, our knowledge about Mercury’s FACs is scarce. Here, to survey the establishment and global pattern of Mercury’s FACs, we used Amitis, a hybrid-kinetic plasma model, to simulate the response of Mercury’s FACs to different interior conductivity profiles and various orientations of the upstream interplanetary magnetic field (IMF). We find that the planet with a conductive interior favors the establishment of FACs, and that IMF orientation controls the pattern of FACs in a similar manner as it does on Earth. But the response of R2-like FACs to IMF orientation differs, thus we cannot simply regard Mercury’s FACs as a scaled-down version of Earth’s. Comparison between our simulations and the previous data analysis suggests that the effective interior conductance to close Mercury’s FACs is ~2.4-3.4 S.