SmCo5 nanoparticles have promising applications in high-density magnetic storage and magnetic nanocomposites. However, conventional calciothermic reduction process yields agglomerated SmCo5 magnets for high temperature annealing, limiting the application and development of SmCo5 nanopartides. In this work, we exploited a novel strategy to fabricate SmCo5 single-crystal nanoparticles by an assistance of graphite oxide sheets. Sm2O3-Co particles coated with graphite oxide sheets were synthesized by solvothermal route, and the following reductive annealing generated SmCo5 particles. The size and magnetic performance of SmCo5 particles can be tuned by manipulating surfactants. The high coercivity of 24.4 kOe and ideal size of 20-100 nm can be achieved in SmCo5 single-crystal nanoparticles. In this technology, graphite oxide sheets can prevent the particles from sintering effectively and sustain the generation of single crystal. (C) 2016 Elsevier B.V. All rights reserved.