Nano-sized α-Al 2 O 3 ceramic-particle-reinforced molybdenum alloy plates were fabricated by a series of processes including hydrothermal synthesis, powder metallurgy, and rolling. The quantitative effect of α-Al 2 O 3 ceramic (particle size and volume fraction) on the microstructures and mechanical properties of molybdenum alloy plates was investigated. Nano-sized α-Al 2 O 3 ceramic particles were obtained and uniformly dispersed in the molybdenum matrix. The α-Al 2 O 3 ceramic refined the molybdenum grains and remarkably increased the microhardness, elastic modulus, and yield strength. The yield strength of the alloy reached a peak value when the α-Al 2 O 3 ceramic content was 1.28 vol% and increased by 61.07%–90.2% compared with that of pure molybdenum after annealing at 1000 °C-1300 °C. A quantitative yield strength model correlating α-Al 2 O 3 particle size, α-Al 2 O 3 volume fraction, molybdenum grain size, and annealing temperature was built. This model attributes the strengthening of alloy to the synergy effects of grain refinement strengthening (σ HP) and Orowan strengthening (σ p). The addition of fine α-Al 2 O 3 ceramic resulted in Orowan strengthening and fine molybdenum grains, thereby increasing yield strength of alloy. [ABSTRACT FROM AUTHOR]