Al2O3 particles with different size (d(50) similar to 1 mu m, 200 nm) and ZrO2 (d(50) similar to 200 nm) were prepared to ZTA UV curable pastes with various bimodal PSDs. A modified Krieger-Dougherty formula was proposed to evaluate the relationship between the PSD and the viscosity. The 30 vol%-fine and 70 vol%-large mixed group owns the minimum porosity about 40.13%, contributing to the lowest viscosity. As ZrO2 increasing to 20 vol%, the viscosities of pastes display an upward trend, but the curing depths (C-d) display a downward trend. This phenomenon is due to the decrease of inter-particle spacing in ZTA paste and the enhancement of light scattering. Finally, ZTA paste containing 15 vol% ZrO2 with bimodal PSDs was prepared with a viscosity < 30000 mPa s. The highest flexural strength, fracture toughness, hardness and relative density of fabricated ZTA ceramic can reach 575 +/- 87 MPa, 7.4 +/- 1.02 MPam(1/2), 19.20 +/- 0.89 GPa and up to 99.4%. (C) 2019 Elsevier B.V. All rights reserved.