Abstract: Molybdenum alloy bars with the different ZrO₂ mass fraction were prepared by powder metallurgy process. The effects of ZrO₂ mass fraction on the microstructure and mechanical properties of the molybdenum alloys were studied by tensile mechanical properties test, hardness test, and optical microscope analysis. The results show that, the grain size of the molybdenum alloys is refined by the addition of ZrO₂. With the increase of the ZrO₂ mass fraction, the hardness and tensile strength at room temperature of molybdenum zirconia alloys increase gradually. When the mass fraction of ZrO₂ is 2.5%, the hardness reaches the highest value as HV₁₀ 240, and the tensile strength reaches the maximum value as 820 MPa.