Fully densitified 3Y-TZP (>98% of theoretical density) ceramic tools have been prepared by gelcasting and sintered with conventional pressureless at 1500 ~ 1600°C. The microstructure and mechanical properties as a function of sintering temperature were investigated. The experiment results indicate that the samples with a range of grain size from 300nm to700nm have high mechanical properties. With the sintering temperature rising, the hardness show no obvious change, the average value is 13.2GPa; while the bending strength have a trend of first increasing then decreasing. The optimal sintering temperature is 1550°C, the bending strength and the fracture toughness all reach the maximum, which is 947 MPa and 8.9MPa.M1/2.