The local atomic structure of nano-quasicrystal-forming Zr 80Pt20 binary glassy alloy was investigated by reverse Monte Carlo modeling based on the results of x-ray diffraction. A prepeak at Q∼17nm-1 originating from the unique bonding between the Pt-Pt pair is observed in the structure factor. Voronoi analysis indicates that an icosahedral-like polyhedron is formed around Pt. It is also found that icosahedral-like polyhedra exist around Zr; however, the fraction of perfect icosahedra is considerably lower than that in the nano-quasicrystalforming Zr70Pd30 glassy alloy. A difference in the local environment between the two binary quasicrystal-forming glassy alloys is suggested.