Lanthanum oxide was introduced to molybdenum powder by liquid-liquid doping and liquid-solid doping, respectively. Mo-La2O3 alloys were prepared by powder metallurgy technology. The particle size distribution and feature of doped particles were investigated by SEM and TEM. The distribution of doped particles in matrix was analyzed, the tensile property of the molybdenum alloy wire was tested, the mechanism of the influence of La2O3 particle on tensile property of Mo-La2O3 alloys was discussed by dislocation pile-up theory. The results show that liquid-liquid doping method can refine La2O3 particles and makes them dispersed uniformly in matrix. The tensile property of the molybdenum alloy wire with 0.6 mm diameter liquid-liquid-doped is better than that liquid-solid-dopinged.