The development of novel anode materials, with superior rate capability, is of utmost significance for the successful realization of sodium-ion batteries (SIBs). Herein, we present a nanocomposite of Nb2O5 and reduced graphene oxide (rGO) by using hydrothermal-assisted microemulsion route. The water-in-oil microemulsion formed nanoreactors, which restrained the particle size of Nb2O5 and shortened the diffusion length of ions. Moreover, the rGO network prevented agglomeration of Nb2O5 nanoparticles and improved electronic conductivity. Consequently, Nb2O5@rGO nanocomposite is employed as anode material in SIBs, delivering a capacity of 195 mAh/g after 200 charge/discharge cycles at 0.2 A/g. Moreover, owing to conductive rGO network, the Nb2O5@rGO electrode rendered a specific capacity of 76 mAh/g at high current density of 10 A/g and maintained 98 mAh/g after 1000 charge/discharge cycles at 2 A/g. The Nb2O5@rGO electrode material prepared by microemulsion method shows promising possibilities for application of SIBs.