We explore the spin-polarized electronic structures and transport properties of Mn@Au-6 cluster. The ab initio modeling is performed by combining the spin-polarized density functional theory with nonequilibrium Green's function formalism. Theoretical results clearly reveal that the central Mn atom anti-ferromagnetically couples with the Au-6 ring and the cluster magnetic moment is 3.0 mu(B). The spin-resolved transmission spectra of Mn@Au-6 sandwiched between two Li (100) electrodes exhibit robust spin filtering effect. The conductance of Mn@Au-6 at the small bias voltage is mainly determined by the spin-up electrons. The findings indicate that Mn@Au-6 cluster holds promise in molecular spintronics applications. (C) 2013 Elsevier B. V. All rights reserved.