ZrO2-Toughened Alumina-Ceramics(ZTA) with Cr2O3 and HfO2 as addition were synthesized by assintering method for solid solution of Al2O3/Cr2O3 and ZrO2/HfO2, and were prepared by pressureless sintering at 1$600^{circ}C$. The effects of Cr2O3 and HfO2 on the thermal and mechanical properties, the sintering mechanism, and the wearness between theory and experiment were investigated. Among three kinds of mechanisms such as stress-induced transformation, microcracking, and crack deflection it contributed to the ZTA system with a few exceptons according to composite. We show that wearness can be estimated sufficiently by HV and KIC through theory and experiment.