The sintering and microstructure of Al2O3-ZrO2 ceramics containing 0~12wt% TiO2 fired at the temperatures from 1400 to 1$600^{circ}C$ were investigated. The shrinkage of powder compacts was increased with increasing amount of TiO2 during heating up to 1$600^{circ}C$ The addition of 2 wt% TiO2 improved the sintered density to about 98% of theoretical density but the sintered density decreased with the addition. of TiO2 higher than 2 wt% The existence of TiO2 promoted the grain growth of both Al2O3 and ZrO2 and the coarsening of grains contribu-ted to the formation of a number of large pores and resulted in a decrease of sintered density. The effect of TiO2 addition was insufficient to retain t-ZrO2 at room temperature. When TiO2 was added above 6wt% the Al2TiO5 compound was formed by the reaction of the excess TiO2 with Al2O3 and it did not suppress the grain growth of Al2O3 and ZrO2