The adsorption of the pentacene (Pn) molecule on the twofold surface of icosahedral (i)-Ag-In-Yb Quasicrystal (QC) have been studied by means of density functional theory (DFT) calculations. We calculate the adsorption energy of Pn at various positions with the molecular axis parallel to the surface and aligned along the fivefold or twofold symmetry axes directions. Pn is stabilised on a Yb trapezoid site from the acute rhombohedron units located between the rhombic triacontahedral clusters. The calculated adsorption energies for different molecular orientations can explain a recent experimental observation.