3Y-TZP containing 0.3∼1.2 wt% of $Al_2$O$_3$ was prepared by slip-casting after attrition milling. The specimen was sintered at 1390∼151$0^{circ}C$ and mechanical characterization and microstructure analysis were conducted. Monoclinic content of the specimen was calculated by XRD. The apparent density of specimen increased with increasing sintering temperature. While above 1470%, the formation of m-ZrO$_2$ degraded the density. The microhardness of specimen decreased with temperature because monoclinic phase increased wit the grain growth. The specimen containing $Al_2$O$_3$ below 0.9 wt% sintered at 143$0^{circ}C$ showed the highest microhardness of 1360 Hv.