Abstract: Mo-W alloys with the W content by mass of 20%~80% were produced by the conventional powder metallurgy technology, the effects of W content on the microstructure and mechanical properties of Mo-W alloy were studied in this paper. The results show that the single phase solid solution is formed by the interdiffusion of W and Mo during the sintering process. The grain size decreases significantly with the increase of W content by mass. The grain size of Mo-80W alloy decreases by 46.5% compared with that of Mo-20W alloy at the sintering temperatures of 1990. With the increase of W content by mass, a℃.double dump. trend of Vickers hardness can be observed, and the peak value appears at 40% W and 60% W. Relative densities and tensile strength generally decline with the W content rising, and the maximum tensile strength of Mo-20W alloy is 514.83 MPa at the sintering temperature of 1990. With the increase of sint℃ ering temperature, the tensile strength of low-tungsten-content alloy (W content by mass: 20%~40%) increases first and then decreases, while the high-tungsten-content alloy (W content by mass: 60%~80%) increases gradually. The failure mode of Mo-W alloy is the mixture of intergranular fracture and transgranular fracture.