Abstract: La2O3/MoSi2 composite particles were prepared by mechanical alloying method and then to prepare sintered molybdenum with different contents of La2O3/MoSi2 composite particles by solid-solid doping method, and the microstructure and mechanical properties of sintered molybdenum were studied. The results show that the doping of La2O3/MoSi2 composite particles could reduce the grain size of sintered molybdenum, and improve the room temperoture bending strength and fracture toughness effectively. When the doping content of La2O3/MoSi2 was 2.0 wt%, the facture toughness was increased by 101.63%. High-temperature compressive strength decreased obviously with increase of temperature, but the compressive strength of sintered molybdenum with doping content of 1.5wt% was still enhance by 1 time comparing with pure sintered molybdenum, The trend of from intergranular fracture to transgranular fracture of sintered molybdenum was nore and more obvious with increase of doping. The black hold appeared in sintered molybdenum with doping content of 0.2wt% to make high-temperature compressive strength decrease.