In this study, Ni-Y2O3 powder was prepared by alloying recomposition oxidation sintering (AROS), solution combustion synthesis (SCS), and conventional mechanical alloying (MA). The microstructure and mechanical properties of the alloys were investigated by spark plasma sintering (SPS). Among the Ni-Y2O3 powders synthesized by the three methods, the AROS powder had approximately 5 nm of Y2O3 crystals uniformly distributed within the Ni particles, whereas the SCS powder contained a mixture of Ni and Y2O3 nanoparticles, and the MA powder formed small Y2O3 crystals on the surface of large Ni particles by milling the mixture of Ni and Y2O3. The average grain size of Y2O3 in the sintered alloys was approximately 15 nm, with the AROS sinter having the smallest, followed by the SCS sinter at 18 nm, and the MA sinter at 22 nm. The yield strength (YS) of the SCS- and MA-sintered alloys were 1511 and 1688 MPa, respectively, which are lower than the YS value of 1697 MPa for the AROS-sintered alloys. The AROS alloy exhibited improved strength compared to the alloys fabricated by SCS and conventional MA methods, primarily because of the increased strengthening from the finer Y2O3 particles and Ni grains.