Abstract: The Ni/Al composites were fabricated by friction stir processing (FSP) by adding different kinds of rare earth oxides (La₂O₃ or CeO₂). The effects of rare earth oxides on the microstructure and properties of Ni/Al composites were studied by SEM, EDS, XRD, electron probe microanalysis (EPMA) and tensile test at room temperature. The results show that Ni/Al composite has more obvious agglomerates of Ni in composite zone. The distribution of Ni power content and size increase in Ni-La₂O₃/Al and Ni-CeO₂/Al composites. La₂O₃ or CeO₂ can reinforce Al-Ni in-situ reaction to produce more reinforced phase. Ni-CeO₂/Al composite has better uniform organization and the volume fraction of Al₃Ni enhances in composite zone. The tensile strength of Ni/Al composite is significantly increased when adding La₂O₃ or CeO₂. The tensile strength of Ni-La₂O₃/Al and Ni-CeO₂/Al composites can reach 221 MPa and 238 MPa, respectively. Compared with the Ni/Al composites (166 MPa), the tensile strength has increased by 33.1% and 43.4%, respectively.