Ni-MF/Al2O3 composite was fabricated using traditional method. The specimens covered with graphite were sintered at 1400°C, and the microstructure and mechanical properties of Ni-MF/Al2O3 composites were studied. Results showed that the flexural strength and fracture toughness of the composites were dramatically changed with the content of nickel. When the content of Ni was 15 wt% and no-coated MF was 10%, the composite obtained better mechanical properties, its flexural strength and fracture toughness were up to 734.40 MPa and 10.17 MPa•m1/2 respectively. The toughening mechanisms of the composites were attributed to the fiber extraction and debonding, metal bridging and deforming plastically.