Incorporation of noble metal into metal–organic frameworks (MOFs) provides an opportunity to fine tune the structure and electronic properties of MOFs materials for many applications. Periodic density functional theory has been used to understand the nature of gold nanoparticle Au_n cluster (n = 2, 4, 6, 8, 10, 12 and 14) inside zirconium-based MOFs (MOF-801). The Au_n clusters were located inside the octahedral and tetrahedral pore of MOF-801 inducing confinement effect toward the structure of Au_n cluster. Various parameters were calculated including the adsorption energy, deformation energy, density of states and intermolecular interaction between Au_n cluster and MOF-801 surfaces. The studies indicate that the adsorption of Au_n cluster is overall exothermic, and the Au_n cluster inside the tetrahedral cage provides a higher stabilization energy. However, the presence of Au_n cluster also induces deformation energy toward the MOF-801 structure. The binding sites of Au_n cluster on the surface of MOF-801 has been assessed using the independent gradient model to unveil possible intermolecular forces between the host and guest system. The electronic bandgap has been assessed showing the possibility to modulate the bandgap energy by increasing the size of Au_n cluster.