Abstract: The Mo-40Cu composite powders were prepared by the hydrothermal and hydrogen reduction method, the effects of sintering process in the hydrogen atmosphere on the microstructure and mechanical properties of the Mo-40Cu composites were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results show that, the optimum process parameters for the powder preparation are 400 ℃ for the hydrothermal temperature and 700 ℃ for the hydrogen reduction temperature, obtaining the homogeneous Mo-40Cu composite powders with the powder particle size of 70~90 nm. The optimum sintering process in the hydrogen atmosphere is sintering at 1300 ℃ for 2 h, the relative density, bending strength, hardness, electrical conductivity, and thermal conductivity are 98.1%, 1060 MPa, HRA 51, 20.8 MS·m^-1, and 191.7 W·m^-1·K^-1, respectively, and the thermal expansion coefficient is 10.8×10^-6 K^-1 at 500~700 ℃. The microstructure of Mo-40Cu alloy is homogenous with the grain size of about 3~4 μm.