This article emphatically studies the whisker toughening mechanism,then analyses on the whisker toughening mechanism of the SiCw/ZrO2 ceramic (Y2O3 molar fraction is 8%) compound materials, and forecasts its whisker toughening effect. Accuracy of toughening mathematic model and calculating equation is proved by calculation and experiment.Thus,it provides important reference for forecasting directly the whisker toughening effects of the SiCw/ZrO2 ceramic (Y2O3 mole fraction is 8%) composite material.