The temperature difference between the growth temperature of plate crystal and the sintering temperature of zirconia toughened alumina (ZTA) is the key to the toughening effect of Pr0.833Al11.833O19 plate crystal on ZTA. In this paper, PrAlO3 precursor was prepared by combustion method, and high active PrAlO3 was formed by pre sintering at 900 ℃. It made the difference between the growth temperature of plate crystal and the sintering temperature of ZTA reach 100 ℃, then the plate crystal with high aspect ratio was obtained, which played a synergistic role in toughening. At the same time, the hydrothermal aging process of ZrO2 is slowed down by the solid dissolution of Pr ions into ZrO2, the microcracks induced by phase transformation are reduced, and the fracture strength and Vickers hardness of ZTA are improved. The results show that, compared with ZTA, the fracture toughness of ZTA reinforced and toughened by Pr0.833Al11.833O19 plate crystal in simulated human environment (hydrothermal aging) increases from 7.13 MPa·m1/2 to 8.97 MPa·m1/2, the fracture strength increases from 654.78 MPa to 687.59 MPa, and the Vickers hardness increases from 18.95 GPa to 19.39 GPa.