Abstract: SiC particles reinforced MoSi₂ matrix composites which was synthexized by hot pressing are studied.Through observation on the microstructure of MoSi₂ and its composites accompanied with the measurement of bending strength,microhardness and fracture toughness,the strengthening toughening mechanism of the materials is revealed.It is shown that the strengthening mechanism of the composites are secondly phase strengthening and grain refining,and the toughening mechanism is a synthetic effect in terms of grain refining,crack deflection and crack branching.