We perform a theoretical calculation in chemically functionalized zigzag graphene nanoribbons, which are terminated with different single atoms or groups, using density functional theory and nonequilibrium Green's function techniques. The calculation results reveal that these different species of atoms and groups have a significant impact on the edge states near Fermi level as well as the spin-dependent electronic transport properties. The calculated I-V curves exhibit negative differential resistance, which can be used for application in molecular spin electronic device. (C) 2013 Elsevier B. V. All rights reserved.