Abstract: The influence of sic whisker volume content on the mechnical properties of the SiCw/ZTA(Y)composites is studied.The results show that the flexure strength and fracture toughness of the composition can be obviously increased by SiC whisker.The composite of 20 vol% SiC whiskers has a flexure strength of 830MPa and a fracture toughness of 9.8MPa·m^1/2.When whisker content is over 20 vol%,the strength of the composite is decreased.The strength of the composite are obviously reinforcing by whisker pull out and cracks deflecting.The tensile stress introduced by the difference the thermal expansion coefficient between whisker and the matrix made more ZrO₂(m). ZrO₂(t)martensitic phase transformation occurs obvious ly,and the increases of the whiskers are profitable to the phase transformation during fracture.Both phase transformation toughening and whisker reinforcing are existed in the composite system.