MoSi2-matitrix composites reinforced with ZrO2 and SiCparticles were fabricated by means of combustion synthesis (CS) com bined with high-energy mechanical milling (MM) and hot-pressing and sintering. The microstructures and mechanical properties of the composites were investigated by X-ray diffractometry (XRD), scanning and transmission electron microsocopy (SEM and TEM), and with a universal meterials testing machine. The results show that SiC particles are mainly distributed inside the grains of the MoSi2s matrix, while ZrO2 particles are distributed at the inter-granular region and produce coalesence and coarseing of the matrix grains during hot pressing. The room-temperature indentation fracture toughness of the composites reinforced with ZrO2 particles non-stabilzed by Y2O3 (the reinforcing agent is coded as OY-PSZ) was higher than that of the composites reinforced with ZrO2 paticles stabilized by 2.5mol% Y2O3 (the reinforcing agent is coded as 2.5Y-PSZ). However, the latter show higher hend strengths. Moreover, the composites hotpressed at 1400℃has a lower hbend strength than hot-presses monolithic MoSi2. It is obvious that there is a synergistic effect of SiC and ZrO2 on the mechanical properties of ZrO2/(MoSi2+SiC) composites.